13 (number)


13 (thirteen) is the
natural number File:Three Baskets.svg, Natural numbers can be used for counting (one apple, two apples, three apples, ...) In mathematics, the natural numbers are those numbers used for counting (as in "there are ''six'' coins on the table") and total order, o ...
and preceding
. Strikingly folkloric aspects of the number 13 have been noted in various cultures around the world: one theory is that this is due to the cultures employing lunar-solar calendars (there are approximately 12.41 lunations per solar year, and hence 12 "true months" plus a smaller, and often portentous, thirteenth month). This can be witnessed, for example, in the "Twelve Days of Christmas" of Western European tradition.

In mathematics

The number 13 is: *along with 15, one of two numbers within the ''teen'' numerical range (13-19) not to use a single-digit number preceding the ''teen'' suffix; instead, it uses the adjective form of three (''thir''d) as the predecessor of said ''teen'' suffix. *the sixth
prime number A prime number (or a prime) is a natural number greater than 1 that is not a Product (mathematics), product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime ...
. *a
star numberImage:Chinese checkers start.svg, 150px, Chinese checkers board has 121 holes. A star number is a centered number, centered figurate number a centered hexagram (six-pointed star), such as the Star of David, or the board Chinese checkers is played on. ...
*the smallest
emirpAn emirp (''prime'' spelled backwards) is a prime number that results in a different prime when its decimal Numerical digit, digits are reversed. This definition excludes the related palindromic primes. The term ''reversible prime'' is used to mean ...
(a prime that is a different prime when its digits are reversed).Wells, D. ''
The Penguin Dictionary of Curious and Interesting Numbers ''The Penguin Dictionary of Curious and Interesting Numbers'' is a reference book for recreational mathematics and elementary number theory written by David Wells. The first edition was published in paperback by Penguin Books in 1986 in the UK, an ...
'', London: Penguin Group. (1987): 67–71.
*one of only three known
Wilson prime A Wilson prime, named after English English usually refers to: * English language English is a West Germanic languages, West Germanic language first spoken in History of Anglo-Saxon England, early medieval England, which has eventually b ...
s. *a Fibonacci number. *a happy number. *the third centered square number. *a lucky number. *equal to the sum of the squares of the digits of its own square in bases 4 and 83. *the smallest number whose fourth power can be written as a sum of two consecutive square numbers (1192 + 1202). Since 52 + 122 = 132, (5, 12, 13) forms a Pythagorean triple. There are 13 Archimedean solids as normally counted, although some include the Elongated square gyrobicupola as a fourteenth. A standard torus can be sliced into 13 pieces with just 3 plane cuts. There are also 13 different ways for the three fastest horses in a horse race to finish, allowing for ties, a fact that can be expressed mathematically by 13 being the third ordered Bell number.

List of basic calculations

In languages


* In all Germanic languages, 13 is the first Compound (linguistics), compound number; the numbers 11 and 12 have their own names. * The Romance languages use different systems: In Italian, 11 is the first compound number (''undici''), as in Romanian (''unsprezece''), while in Spanish and Portuguese, the numbers up to and including 15 (Spanish ''quince'', Portuguese ''quinze''), and in French up to and including 16 (''seize'') have their own names. This is also the case in most Slavic languages, Hindi-Urdu and other South Asian languages.


In Germany, according to an old tradition, 13 (''dreizehn''), as the first compound number, was the first number written in digits; the numbers 0 (''null'') through 12 (''zwölf'') were spelled out. The ''Duden'' (the German standard dictionary) now calls this tradition (which was actually never written down as an official rule) outdated and no longer valid, but many writers still follow it.

In religion


In Shia Islam, 13 signifies the 13th day of the month of Rajab (the Lunar calendar), which is the birth of Imam Ali. 13 also is a total of 1 Prophet and 12 Imams in the Islamic School of Thought. However, in Sunni Islam, the number 13 bears no symbolic significance.


The apparitions of the Virgin of Fátima in 1917 were claimed to occur on the 13th day of six consecutive months. In Catholic devotional practice, the number thirteen is also associated with Saint Anthony of Padua, since his feast day falls on June 13. A traditional devotion called the Thirteen Tuesdays of St. Anthony involves praying to the saint every Tuesday over a period of thirteen weeks. Another devotion, St. Anthony's Chaplet, consists of thirteen decades of three beads each.


According to famous Sakhi (Evidence) or story of Guru Nanak Dev Ji, when he was an accountant at a town of Sultanpur Lodhi, he was distributing groceries to people. When he gave groceries to the 13th person, he stopped because in Gurmukhi and Hindi the word 13 is called Terah, which means yours. And Guru Nanak Dev Ji kept saying, "Yours, yours, yours..." remembering God. People reported to the emperor that Guru Nanak Dev Ji was giving out free food to the people. When treasures were checked, there was more money than before. The Vaisakhi, which commemorates the creation of "Khalsa" or pure Sikh was celebrated on April 13 for many years.


* In Judaism, 13 signifies the age at which a boy matures and becomes a Bar and Bat Mitzvah, Bar Mitzvah, ''i.e.'', a full member of the Jewish faith (counts as a member of Minyan). * The number of Jewish principles of faith, principles of Jewish faith according to Maimonides. * According to Rabbinic Judaism, Rabbinic commentary on the Torah, God has 13 Attributes of Mercy.


Since beginning of the Nowruz tradition, the 13th day of each new year is called Charsamba akhsami, a festival dedicated to pranks and spending time outdoors.


* The Thirteen Classics is considered to be a part of the Chinese classics.



The number 13 is considered an unlucky number in some countries. The end of the Mayan calendar's 13th Baktun was superstitiously feared as a harbinger of the apocalyptic 2012 phenomenon. Fear of the number 13 has a specifically recognized phobia, triskaidekaphobia, a word coined in 1911. The superstitious sufferers of triskaidekaphobia try to avoid bad luck by keeping away from anything numbered or labelled thirteen. As a result, companies and manufacturers use another way of numbering or labelling to avoid the number, with hotels and tall buildings being conspicuous examples (thirteenth floor). It is also considered unlucky to have thirteen guests at a table. Friday the 13th has been considered an unlucky day. There are a number of theories as to why the number thirteen became associated with bad luck, but none of them have been accepted as likely. *The Last Supper: At Jesus Christ's last supper, there were thirteen people around the table, counting Christ and the twelve apostles. Some believe this is unlucky because one of those thirteen, Judas Iscariot, was the betrayer of Jesus Christ. From the 1890s, a number of English language sources relate the "unlucky" thirteen to an idea that at the Last Supper, Judas Iscariot, Judas, the Disciple (Christianity), disciple who betrayed Jesus, was the 13th to sit at the table. *Knights Templar: On Friday, 13 October 1307, King Philip IV of France ordered the arrest of the Knights Templar, and most of the knights were tortured and killed. *Full Moons: A year with 13 full moons instead of 12 posed problems for the monks in charge of the calendars. "This was considered a very unfortunate circumstance, especially by the monks who had charge of the calendar of thirteen months for that year, and it upset the regular arrangement of church festivals. For this reason, thirteen came to be considered an unlucky number." However, a typical century has about 37 years that have 13 full moons, compared to 63 years with 12 full moons, and typically every third or fourth year has 13 full moons. *A Repressed Lunar Cult: In ancient cultures, the number 13 represented femininity, because it corresponded to the number of lunar (menstrual) cycles in a year (13 x 28 = 364 days). The theory is that, as the solar calendar triumphed over the lunar, the number thirteen became anathema. *Hammurabi's Code: There is a myth that the earliest reference to thirteen being unlucky or evil is in the Babylonian Code of Hammurabi (circa 1780 BC), where the thirteenth law is said to be omitted. In fact, the original Code of Hammurabi has no numeration. The translation by L.W. King (1910), edited by Richard Hooker, omitted one article: If the seller have gone to (his) fate (i. e., have died), the purchaser shall recover damages in said case fivefold from the estate of the seller. Other translations of the Code of Hammurabi, for example the translation by Robert Francis Harper, include the 13th article.


*France: 13 was traditionally considered a lucky number in France prior to the First World War, and was used in numerical form as a good luck symbol on postcards and charms. *Italy: 13 was the lucky number in the Italian football pools (''Totocalcio''). The Italian expression ''"fare tredici"'' (literally, "make thirteen") means to hit the jackpot.


Colgate University also considers 13 a lucky number. They were founded in 1819 by 13 men with 13 dollars, 13 prayers and 13 articles. (To this day, members of the Colgate community consider the number 13 a good omen.) In fact, the campus address is 13 Oak Drive in Hamilton, New York, and the male ''a cappella'' group is called the Colgate 13. In the Mayan Tzolk'in calendar, trecenas mark cycles of 13-day periods. The pyramids are also set up in 9 steps divided into 7 days and 6 nights, 13 days total. In the standard 52-card deck of playing cards there are four suits, each of 13 ranks. A baker's dozen, devil's dozen, long dozen, or long measure is 13, one more than a standard dozen. The thirteenth loaf is called the vantage loaf because it is considered advantageous overall to get 13 loaves for the price of 12. In Arthurian legend, which was recorded in Medieval texts, King Arthur is resting in Avalon with the twelve greatest knights of the Round Table, totalling 13, and will return when his country is in peril. The Thirteen Treasures of the Island of Britain, Thirteen Treasures of Britain are a series of magical items listed in late Medieval texts. The Thirteen Postures of Tai Chi are thirteen postures (consisting of Eight Gates and Five Steps) which are considered to be of fundamental importance in the practice of Tai Chi. In astronomy there are 13 star constellations in the zodiac (including Ophiuchus); this can be compared with astrology where there are 12 signs of the zodiac. In Judaism, 13 signifies the age at which a boy matures and becomes a Bar Mitzvah, i.e., a full member of the Jewish faith (counts as a member of Minyan). The number of principles of Jewish faith according to Maimonides. According to Rabbinic commentary on the Torah, God has 13 Attributes of Mercy. In a tarot card deck, XIII is the card of Death, usually picturing Four Horsemen of the Apocalypse#Pale Horse, the Pale horse with its rider.


*In Judaism, thirteen signifies the age at which a boy matures and becomes a Bar and Bat Mitzvah, Bar Mitzvah, ''i.e.'', a full member of the Jewish faith (is qualified to be counted as a member of Minyan). *Thirteen is the minimum age of consent in Argentina, Burkina Faso, Japan, Niger, and two Mexico, Mexican states. *On many social media platforms in the United States, thirteen is the standard minimum age to be allowed to create an account in compliance with Children's Online Privacy Protection Act (COPPA). *This is the age at which the Entertainment System Rating Board (ESRB) assesses for T-rated games and the Motion Picture Association recommends movies with a PG-13 rating.


*The United States of America was created from Thirteen Colonies, thirteen British colonies and as such, the number thirteen is a commonly recurring motif in United States heraldry, American heraldry. For example, there are thirteen stars on the Great Seal of the United States and there are thirteen stripes on the Flag of the United States, American flag. **The first flag of the United States bore thirteen stripes, alternating red and white, and thirteen white stars in the blue union. The thirteen stripes represented the Thirteen Colonies from which the United States was created, and the thirteen stars represented the number of states in the new nation. When two new states were added to the Union in 1795, the flag bore fifteen stars and fifteen stripes. With the addition of five new states in 1818, the number of stripes was re-set and permanently fixed at thirteen. **The Great Seal of the United States bears many images of the number thirteen, representing the Thirteen Colonies from which the United States was created. On the Seal's observe, the overhead glory bears thirteen stars. The chest shield in front of the spread eagle bears thirteen stripes (seven white and six red). In the eagle's right talon, it holds the Olive Branch of Peace, bearing thirteen olives and thirteen olive leaves. In the eagle's left talon, it holds the Weapons of War, consisting of thirteen arrows. In the eagle's mouth, it holds a scroll bearing the national motto "E Pluribus Unum" (which, by coincidence, consists of thirteen letters). On the Seal's reverse, the unfinished pyramid consists of thirteen levels. *The Thirteenth Amendment to the United States Constitution abolished slavery and involuntary servitude. *Apollo 13 was a NASA Moon mission famous for being a "successful failure" in 1970.

In sports

* The number 13 was not used in the Indianapolis 500 from 1915 to 2002. It was not permitted for use between 1926 and 2002. In 2009, E.J. Viso, driving for HVM Racing in the 2009 IndyCar Series season, drove a green number 13 car full-time, despite terrible superstitions about it in motorsports. * The number 13 was not used in Formula One from 1977 to 2013. * In rugby league: ** Each side has 13 players on the field at any given time. ** The jersey number 13 is worn by the starting loose forward or lock forward in most competitions. An exception is in the Super League, which uses static squad numbering. * In rugby union, the jersey number 13 is worn by the Rugby union positions, outside centre. * In triathlon, the number 13 is not used. As such, the numbering goes 11, 12, ''14'', 15 under the current numbering system. *In Pétanque, Petanque, standard games are won when a team reaches the score of 13 points. A 13–0 score is called Fanny. * Effective with the 2020 season, Major League Baseball teams are allowed no more than 13 pitchers on their active rosters at any time during the season. The main exception is from September 1 to the end of the regular season, when this number increases to 14. * In NCAA Division I men's college basketball, teams are allowed to provide Athletic scholarship, scholarships to no more than 13 players at any given time.

In TV, films and literature

*13th (film), ''13th'', a 2016 documentary. *13 (musical), ''13'' (musical), a 2007 musical. *13 (2010 film), ''13'' (film), an English-language remake of the 2005 French film 13 Tzameti. *Thirteen (2003 film), ''Thirteen'' (film), a 2003 American film. *Thirteen (TV series), ''Thirteen'' (TV series), a 2016 British five-part police drama. *Number 13 (film), ''Number 13'' (film), an uncompleted Hitchcock 1922 film. *''13 Tzameti'', a 2005 French film ("Tzameti" means "13" in Georgian). *''13 Ghosts'' is a 1960 horror film. **''Thirteen Ghosts'' a 2001 remake. *Thirteen (House), Thirteen is the nickname of Dr. Remy Hadley on the American medical drama ''House (TV series), House'' played by Olivia Wilde. *''13 Assassins (2010 film), 13 Assassins'' is a 2010 film by Japanese director Takashi Miike. *''The Thirteen'' is a 1936 Soviet war film by Mikhail Romm. *''The 13th Warrior'' is a 1999 historical fiction action film starring Antonio Banderas. *''District 13'' is a 2004 French film (with David Belle). *''Apollo 13 (film), Apollo 13'' is a 1995 American film. *''Warehouse 13'' is a television show about the 13th warehouse in the line of warehouses that store supernatural artifacts. *''Friday the 13th (franchise), Friday the 13th'' is a horror film series involving a mass murderer named Jason Voorhees. *''Friday the 13th: The Series'' is a syndicated American-Canadian horror television series, that originally ran from 1987 to 1990. *''The 13 Ghosts of Scooby-Doo'': Seventh incarnation of the Hanna-Barbera Scooby-Doo cartoon franchise, first run 1985–1986. *''The Thirteenth Floor'' is a 1999 sci-fi film. *''Golgo 13'' is the oldest manga still in publication centered around a self-titled assassin. It is the second or third best selling manga in history. *''Yavarum Nalam, 13B/Yaavarum Nalam'' is a 2009 Hindi/Tamil Horror movie starring R Madhavan. *''Thirteen Reasons Why'' is a novel containing 13 tapes received by a student learning of his classmate's suicide and death. *The Thirteenth Doctor, the 13th incarnation of the The Doctor (Doctor Who), titular character of ''Doctor Who'', played by Jodie Whittaker. *In ''The Hobbit'', the Company of Thorin Oakenshield consists of 13 Dwarves trying to reclaim their homeland from the dragon Smaug (Thorin Oakenshield, Fíli, Kíli, Óin, son of Gróin, Óin, Glóin, Balin (Middle-earth), Balin, Dwalin, Bifur, Bofur, Bombur (Middle-earth), Bombur, Dori (Middle-earth), Dori, Nori (Middle-earth), Nori and Ori (Middle-earth), Ori). *In ''The Wheel of Time'' series, there were 13 Forsaken (Chosen) sealed away with their master, the Dark One, at the end of the Age of Legends, and later released in the Third Age (Aginor, Asmodean, Balthamel, Be'lal, Demandred, Graendal, Ishamael, Lanfear, Mesaana, Moghedien, Rahvin, List of Wheel of Time characters#S, Sammael and Semirhage).

See also

* List of highways numbered 13


{{Authority control Integers Numerology Triskaidekaphobia Superstitions about numbers