31 Facts About Number 31: Shocking Facts Revealed

number 31 on a frame

31 Facts About Number 31: Shocking Facts Revealed

  1. A cube with a volume of 31 cubic inches would have a height of approximately 0.3 feet.
  2. The sum of 31’s digits is 4.
  3. In Roman numerals, 31 is written as XXXI.
  4. 31 years is approximately 977,616,000 seconds.
  5. 31 is also recognized as a Mersenne Prime.
  6. The Cyrillic alphabet contains more letters than the English alphabet, totaling 31 characters.
  7. These months end with 31 days: January, March, May, July, August, October, and December.
  8. Thirty-one, or Trente et un, is a card game for 2 to 7 players, where the goal is to assemble a hand totaling 31.
  1. Months with 31 days include January, March, May, July, August, October, and December.
  2. In Roulette, 31 is a black number.
  3. The country code for the Netherlands is +31.
  4. Jackson Pollock, a leading American abstract expressionist artist, created u0022One: Number 31,u0022 one of his largest paintings.
  5. The sum of the first eight digits of π (Pi) equals 31.
  6. In Trenton, Tennessee, there’s a town named Trenton where the speed limit is set at 31 miles per hour (49.89 kilometers per hour).
  7. One tablespoon of unmelted butter contains 31 milligrams of cholesterol, equivalent to 0.0011 ounces.
  8. 31 is the number of flavors Baskin-Robbins offers in Japan (their name translates to u002231 Ice Creamu0022).

Table of Contents

1. In numerology, the number 31 is associated with creativity, independence, and self-expression.

In numerology, the number 31 is associated with creativity, independence, and self-expression. People influenced by this number are often seen as innovative and original thinkers.

Combining the numbers 3 and 1 brings together the energy of creativity and the drive for new beginnings. This number encourages individuals to follow their unique paths and express their true selves.

Those connected to the number 31 are believed to thrive in environments that allow for personal freedom and artistic endeavors.

2. The month of January has 31 days.

January, the first month of the Gregorian calendar, stands out among its counterparts with its 31-day duration. This makes it unique, as the other months have varying lengths, ranging from 28 to 30 days. 

The extended span of January provides an additional day for us to kickstart the new year, allowing for more time to reflect, set goals, and embark on new ventures. Its longer duration also offers a sense of anticipation and possibility, setting the tone for the year ahead.

3. The number 31 is a prime number, meaning it is only divisible by 1 and itself.

In mathematics, prime numbers are integers greater than 1 that can only be divided evenly by 1 and themselves. The number 31 falls into this category, making it a prime number. 

Prime numbers have fascinated mathematicians for centuries, and they possess unique properties that make them integral to various mathematical concepts and encryption algorithms. The fact that 31 cannot be divided by any other number except 1 and 31 adds to its mathematical intrigue and significance.

4. On July 31, 1971, Apollo 15 astronauts became the first to drive a vehicle on the moon.

Moon buggy debut. On this day in 1971.

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On July 31, 1971, Apollo 15 astronauts made history by becoming the first to drive a vehicle on the moon. Dave Scott and Jim Irwin were at the helm of the Lunar Roving Vehicle, exploring the lunar surface with unprecedented mobility.

Eager to make the most of this opportunity, Scott was not about to pass by an interesting rock without stopping. This mission marked a significant milestone in lunar exploration, allowing the astronauts to cover more ground and collect valuable geological samples.

5. The 31st President of the United States was Herbert Hoover.

Herbert Hoover, the 31st President of the United States, held office during a critical period in American history. He took office in 1929, just months before the infamous stock market crash that triggered the Great Depression. 

Hoover’s presidency was defined by his efforts to address the economic crisis and mitigate its effects on the American people. 

Despite his best intentions, his administration faced significant challenges and criticism for responding to the worsening economic conditions.

6. The number 31 is often used to symbolize freedom and liberation.

The number 31 has come to represent freedom and liberation in various contexts. Its association with personal freedom stems from its numerological traits emphasizing independence, creativity, and self-expression. 

Additionally, 31 is often associated with attaining goals, pursuing dreams, and breaking free from limitations.

7. In Shakespeare’s play “Macbeth,” there are 31,534 words in total.

“Macbeth,” one of William Shakespeare’s renowned tragedies, captivates readers and audiences with its gripping storyline and poetic language. Within the play, the Bard ingeniously crafts a narrative that delves into themes of ambition, power, and the consequences of unchecked desires. 

Interestingly, the complete script of “Macbeth” consists of precisely 31,534 words, showcasing Shakespeare’s mastery of language and his ability to create a rich tapestry of dialogue and soliloquies.

8. In Judaism, the holiday of Hanukkah lasts for 8 days, and the menorah used during this festival has 31 total lights.

brown star statue
This 8-day festival features the menorah.

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Hanukkah, the Festival of Lights, is a joyous celebration in Judaism that commemorates the rededication of the Second Temple in Jerusalem. This holiday lasts for eight days and holds profound meaning for Jewish communities worldwide. Throughout the festival, a special menorah, known as a Hanukkiah, is lit each night. 

The Hanukkiah typically consists of nine branches, with one candle lit on the first night and an additional candle added each subsequent night. By the eighth night of Hanukkah, 31 lights shine brightly, symbolizing the triumph of light over darkness and the enduring spirit of hope.

9. The longest month of the year is July in a leap year, which has 31 days.

While most months have 30 or 31 days, July is the longest month in a leap year. Leap years occur every four years and consist of an additional day, known as leap day, on February 29th. 

This adjustment helps align the calendar with the Earth’s orbit around the sun. Consequently, July, the month following February in a leap year, gains an extra day, extending its duration to a total of 31 days.

10. The number 31 is the atomic number of gallium, a chemical element.

Gallium, a unique chemical element represented by atomic number 31 on the periodic table, possesses fascinating properties and applications. With a low melting point, this silvery metal is useful in various fields, including electronics, semiconductors, and medical imaging. 

Gallium’s ability to transform from a solid to a liquid state at relatively low temperatures makes it valuable in thermometers and as a component in certain alloys.

11. On August 31, 1962, Trinidad and Tobago gained independence from the United Kingdom.

On August 31, 1962, Trinidad and Tobago gained independence from the United Kingdom, ending over 160 years of British colonial rule. The twin-island nation embarked on a new journey as an independent state within the Commonwealth.

The country’s first Prime Minister, Dr. Eric Williams, was pivotal in leading the nation to independence. Celebrations included flag-raising ceremonies, parades, and cultural events, marking a significant moment in the nation’s history.

The new national flag, featuring red, white, and black, symbolized the country’s unique identity and unity.

12. In some Christian traditions, the 31st of October is observed as All Hallows’ Eve.

In some Christian traditions, October 31st is All Hallows’ Eve.

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All Hallows’ Eve, commonly known as Halloween, is religiously significant in some Christian traditions. Celebrated on the 31st of October, it serves as the precursor to All Saints’ Day, which occurs on November 1st. 

All Hallows’ Eve has historical roots in the ancient Celtic festival of Samhain, marking the end of the harvest season and the beginning of winter. In Christian observance, this evening is a time to remember and honor departed loved ones and saints who have attained heavenly status. 

The traditions surrounding All Hallows’ Eve include lighting candles, visiting cemeteries, and attending church services.

13. On March 31, 1966, the Soviet Union launched Luna 10, the first spacecraft to orbit the Moon.

On March 31, 1966, the Soviet Union launched Luna 10, the first spacecraft to orbit the Moon and the first human-made object to orbit anybody beyond Earth. The mission aimed to achieve a lunar orbit and gather data on the lunar environment.

The launch coincided with the Twenty-third Congress of the Communist Party of the Soviet Union. Luna 10’s scientific payload included instruments to study gamma rays, magnetic fields, and micrometeoroids.

The spacecraft successfully entered lunar orbit on April 3, 1966, and transmitted valuable scientific data back to Earth.

14. On December 31st, people worldwide celebrate New Year’s Eve.

December 31st, the final day of the Gregorian calendar, is universally celebrated as New Year’s Eve. It is a time of reflection, celebration, and anticipation for the coming year. People gather with friends, family, and loved ones to bid farewell to the passing year and welcome the new one with joy and hope. 

Festivities include parties, fireworks displays, countdowns, and the singing of “Auld Lang Syne.” New Year’s Eve serves as a collective moment of closure and renewal, where people set goals, make resolutions, and embrace the possibilities that lie ahead.

15. The Thirty-One Years’ War (1618-1648) was a major European conflict.

The Thirty Years’ War, a protracted and devastating conflict that engulfed Europe from 1618 to 1648, is significant in history. Fought primarily in the Holy Roman Empire, it drew in numerous European powers and became one of the most destructive wars of the time. 

The war originated in political and religious tensions, including conflicts between Protestant and Catholic states. It resulted in significant territorial changes, religious realignments, and the rise of powerful nation-states. 

The Thirty Years’ War marked a turning point in European history, shaping the geopolitical landscape and laying the foundation for future conflicts and alliances.

16. The 31st parallel north is an imaginary line that circles the Earth, passing through countries like Iraq, Iran, and the United States.

Earth with clouds above the African continent, illustrating the diversity and connectivity of our planet, similar to the diverse "Facts About Number 31" that span various fields and cultures.
31st parallel north: Circles Iraq, Iran, and the U.S.

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The 31st parallel north is an imaginary line of latitude that extends around the Earth, crossing various countries and regions. It passes through numerous significant locations, including parts of Iraq, Iran, Saudi Arabia, the United Arab Emirates, the southern United States, and Mexico’s northern border. 

The 31st parallel north is of geographical and geopolitical importance. It demarcates regions with distinct climates, cultural influences, and historical significance. This latitude line reminds us of the diverse landscapes and interconnectedness of countries along its path.

17. In binary code, the decimal number 31 is represented as 11111.

In binary code, the decimal number 31 is represented as 11111. This five-bit binary number is significant in computer science and digital systems. Binary code is a base-2 numeral system used by almost all modern computers and digital devices.

Each digit in a binary number represents an increasing power of 2, starting from the rightmost digit. For 31, the binary sequence (11111) equates to 2˄4+2˄3+2˄2+2˄1+2˄0, summing to 31.

18. On October 31, 1926, famed magician Harry Houdini died in Detroit, Michigan.

On October 31, 1926, famed magician Harry Houdini died in Room 401 of Grace Hospital in Detroit, Michigan, fittingly on Halloween. The cause of death was peritonitis from a ruptured appendix.

Houdini, known for his death-defying escape acts, had amazed audiences with feats such as escaping from handcuffs, straitjackets, and water-filled tanks. Despite his uncanny ability to seemingly cheat death on stage, the 52-year-old magician’s sudden demise shocked fans worldwide. His gravesite is located at Machpelah Cemetery in Queens, New York.

19. Route 31 is a major highway running through multiple states in the United States.

Route 31 is a major highway running through multiple states in the United States. It stretches from northern Michigan to southern Alabama, covering a distance of over 1,200 miles.

The highway passes through states like Indiana, Kentucky, and Tennessee, serving as a vital corridor for local and interstate travel. Route 31 connects numerous towns and cities along its route, providing access to various cultural, historical, and natural attractions.

20. In New York City, 31st Street runs through the borough of Manhattan, known for its bustling activity.

In New York City, 31st Street runs through the borough of Manhattan, known for its bustling activity. This street is a major east-west thoroughfare stretching from the Hudson River to the East River.

Along 31st Street, you’ll find a mix of residential buildings, office complexes, and popular landmarks. Notable places include the historic Hotel Pennsylvania and the bustling Penn Station, one of the city’s main transportation hubs.

21. On July 31st, 1975, Jimmy Hoffa, an American labor union leader, went missing and was declared legally dead in 1982.

Jimmy Hoffa black and white photo
Jimmy Hoffa disappears, declared dead in 1982.

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The disappearance of Jimmy Hoffa, a prominent American labor union leader, continues to intrigue and baffle investigators and the public alike. On July 31st, 1975, Hoffa vanished under mysterious circumstances, and despite extensive efforts to locate him, no trace of his whereabouts has been found. 

His unexplained disappearance captivated the nation and sparked numerous theories and speculations. In 1982, seven years after his disappearance, Hoffa was declared legally dead.

22. The 31st Amendment to the United States Constitution, ratified in 1865, abolished slavery and involuntary servitude, except as punishment for a crime.

The 31st Amendment to the United States Constitution holds immense historical significance in the fight for equality and freedom. Ratified in 1865, this amendment played a pivotal role in the aftermath of the American Civil War. 

The 31st Amendment declared the abolition of slavery and involuntary servitude, except as a form of punishment for individuals convicted of crimes.

23. On July 31, 1965, author J.K. Rowling, known for the Harry Potter series, was born.

On July 31, 1965, author J.K. Rowling, known for the Harry Potter series, was born. Joanne Rowling was born in Yate, Gloucestershire, England. Her Harry Potter books have become some of the best-selling novels in history.

The series has been translated into numerous languages and adapted into a successful film franchise. Rowling’s work has significantly impacted literature and popular culture worldwide.

24. On March 31, 1889, the Eiffel Tower was officially completed and opened to the public.

The Eiffel Tower, designed by Gustave Eiffel and located in Paris, France, was officially completed and opened to the public on March 31, 1889. This iconic Parisian landmark stands at 324 meters tall and was originally constructed as the entrance arch for the 1889 Exposition Universelle, a world’s fair held to celebrate the 100th anniversary of the French Revolution.

The tower quickly became a symbol of French engineering prowess. Today, it remains one of the most visited monuments in the world, attracting millions of tourists annually.

25. In Roman numerals, the number 31 is represented as XXXI.

Clock with roman number on it
Roman numeral for 31: XXXIRoman numeral for 31: XXXI.

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Roman numerals, an ancient numerical system developed in ancient Rome, have endured as a symbolic representation of numbers in various contexts. In this system, the number 31 is denoted by the combination of four letters: XXXI. 

Each letter represents a specific value—X represents 10, and I represents 1. By combining the letters, the Romans expressed the value of 31. Roman numerals continue to be used in certain domains, such as clock faces, monarchial regnal names, and historical dates, connecting us to the rich legacy of the Roman civilization.

26. Baskin-Robbins is famous for its 31 flavors of ice cream.

Baskin-Robbins is famous for its 31 flavors of ice cream, representing a different flavor for each day of the month. This unique concept makes it the only ice cream chain in the world with such a variety.

The company was founded by brothers-in-law Burt Baskin and Irv Robbins. Burt married Irv’s sister Shirley in 1942, solidifying their family and business partnership. Since its founding, Baskin-Robbins has become a beloved ice cream brand globally.

27. On December 31, 1999, the world celebrated the turn of the millennium.

On December 31, 1999, the world celebrated the turn of the millennium. As the clock struck midnight, people across the globe welcomed the year 2000 with grand festivities.

Major cities hosted spectacular fireworks displays, and iconic landmarks were illuminated. This moment marked the end of the 20th century and the beginning of the 21st century.

28. On May 31st, World No Tobacco Day is observed.

World No Tobacco Day, observed on May 31st each year, is of global significance in the ongoing efforts to combat tobacco-related health issues. Established by the World Health Organization (WHO), this day aims to raise awareness about the harmful effects of tobacco use on individuals’ health and society as a whole. 

It serves as a platform to educate the public about the risks of smoking, secondhand smoke, and tobacco addiction.

29. On October 31, 1517, Martin Luther posted his 95 Theses, sparking the Protestant Reformation.

portait of martin luther
October 31, 1517, Martin Luther’s 95 Theses sparked religious change.

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On October 31, 1517, Martin Luther, a priest and scholar, allegedly nailed his 95 Theses to the door of the Castle Church in Wittenberg, Germany. In these theses, Luther criticized the Roman Catholic Church’s corruption, particularly condemning Johann Tetzel’s sale of indulgences, which funded the renovation of St. Peter’s Basilica in Rome.

Despite the local ban on indulgences by Prince Frederick III the Wise, many church members sought them elsewhere, spurring Luther to act.

His 95 Theses were swiftly translated from Latin into German and widely disseminated, leading to his excommunication by Pope Leo X in 1521. This pivotal moment initiated the Protestant Reformation, drastically altering Europe’s religious landscape.

30. The 31st state to join the United States of America was California, admitted on September 9, 1850.

The United States of America has a rich history of statehood, and each state’s addition marks a significant milestone. On the West Coast, California became the 31st state to join the Union on September 9, 1850. 

Known for its diverse landscapes, cultural vibrancy, and economic importance, California’s admission played a pivotal role in expanding the United States. From the iconic cities of Los Angeles and San Francisco to the breathtaking natural wonders of Yosemite and the Pacific coastline, California’s diverse offerings have made it a popular destination and a state that continues to shape the country’s cultural, technological, and economic landscapes.

31. On August 31, 1997, the world mourned the tragic death of Princess Diana in a car accident, marking a significant moment in history.

On August 31, 1997, the world mourned the tragic death of Princess Diana in a car accident, marking a significant moment in history. During the early hours in Paris, Diana, Princess of Wales, succumbed to injuries sustained in a fatal crash in the Pont de l’Alma tunnel.

Her partner, Dodi Fayed, and the driver, Henri Paul, were also killed, while bodyguard Trevor Rees-Jones was the sole survivor.

A 1999 French investigation concluded that Paul lost control of the vehicle at high speed while intoxicated. Diana’s death at 36 sparked an outpouring of public grief, and an estimated 2.5 billion people watched her televised funeral.


One notable example is J.B. Priestley’s novel The 31st of June, which explores the concept of alternate realities and the significance of a specific date.

Yes, there are significant historical events associated with the number 31, such as the 31st President of the United States, Herbert Hoover, and the 31st state to join the United States, California.

In astronomy, the moon’s synodic period is approximately 29.53 days, which is close to 31 days, making it an interesting number for lunar cycles.

The number 31 holds cultural significance in various contexts. For example, Halloween falls on October 31st; in some traditions, 31 is considered a lucky or mystical number.

In sports, the number 31 is often associated with athletes who wear it as their jersey number, such as basketball player Reggie Miller and ice hockey goalie Carey Price.

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