23 (number)

:"This article is about the number 23. For the year, see 23. For the movies, see 23 (film) and The Number 23. For other uses, see 23 (disambiguation)"Number|number = 23
range = 20s
cardinal = twenty-three
ordinal = rd
ordinal text = twenty-third
numeral =
factorization = prime
prime =
divisor = 1, 23
roman = XXIII
unicode =
greek prefix =
latin prefix =
bin = 10111
oct = 27
duo =
hex = 17
misc =

23 (twenty-three) is the natural number following 22 and preceding 24.

In mathematics

Twenty-three is the ninth prime number, the smallest odd prime which is not a twin prime. Twenty-three is also the fifth factorial prime, the second Woodall prime. It is an Eisenstein prime with no imaginary part and real part of the form $3n\; -\; 1$.

The fifth Sophie Germain prime and the fourth safe prime, 23 is the next to last member of the first Cunningham chain of the first kind to have five terms (2, 5, 11, 23, 47). Since 14! + 1 is a multiple of 23 but 23 is not one more than a multiple 14, 23 is a Pillai prime. 23 is the smallest odd prime to be a highly cototient number, as the solution to "x" - φ("x") for the integers 95, 119, 143, 529.

Twenty-three is the aliquot sum of two integers; the discrete biprimes 57 and 85 and is the base of the 23-aliquot tree.

23 is the first prime $P$ for which unique factorization of cyclotomic integers based on the $P$'th root of unity breaks down. The sum of the first 23 primes is 874, which is divisible by 23, a property shared by few other numbers. [OEIS|id=A045345] [ [http://www.primepuzzles.net/puzzles/puzz_031.htm Puzzle 31.- The Average Prime number, APN(k) = S(Pk)/k] from the The Prime Puzzles & Problems Connection website]

In the list of Fortunate numbers, 23 occurs twice, since adding 23 to either the fifth or eighth primorial gives a prime number (namely 2333 and 9699713).

23 also has the distinction of being one of two integers that cannot be expressed as the sum of fewer than 9 cubes of integers (the other is 239). See Waring's problem.

23 is a Wedderburn-Etherington number. The codewords in the perfect (non-extended) binary Golay code are of size 23.

According to the birthday paradox, in a group of 23 (or more) randomly chosen people, the probability is more than 50% that some pair of them will have the same birthday.

There were 23 problems on David Hilbert's famous list of unsolved mathematical problems, presented to the International Congress of Mathematicians in Paris in 1900.

In base 10, 23 is the second Smarandache-Wellin prime, as it is the concatenation of the base 10 representations of the first two primes (2 and 3) and is itself also prime. It is also a happy number in base 10. 23! is 23 digits long in base 10. There are only three other numbers that have this property: 1, 22, and 24.

The natural logarithms of all positive integers lower than 23 are known to have binary
BBP-type formulae. [http://www.math.grinnell.edu/~chamberl/papers/bbp.pdf]

The first 6 digits of Pi are 3.14159 which all add up to 23.

In science

*The atomic number of vanadium.
*The atomic mass number of the stable isotope of sodium.
*Normal human sex cells have 23 chromosomes. [H. Wramsby, K. Fredga, P. Liedholm, "Chromosome analysis of human oocytes recovered from preovulatory follicles in stimulated cycles" "New England Journal of Medicine" 316 3 (1987): 121 - 124] Other human cells have 46 chromosomes, arranged in pairs. [Barbara J. Trask, "Human genetics and disease: Human cytogenetics: 46 chromosomes, 46 years and counting" "Nature Reviews Genetics" 3 (2002): 769. "Human cytogenetics was born in 1956 with the fundamental, but empowering, discovery that normal human cells contain 46 chromosomes."]

In technology

23 is the TCP/IP port used for telnet and is the default for the telnet command.

In religion

*Psalm 23, also known as the Shepherd Psalm, is possibly the most quoted and best known Psalm. [Miriam Dunson, "A Very Present Help: Psalm Studies for Older Adults". New York: Geneva Press (1999): 91. "Psalm 23 is perhaps the most familiar, the most loved, the most memorized, and the most quoted of all the psalms."] Psalms is also the 23rd book in the Douay-Rheims Bible.
*In Islam, the Qur'an was revealed in a total of 23 years to Muhammad. ["Living Religions: An Encyclopaedia of the World's Faiths," Mary Pat Fisher, 1997, page 338, I.B. Tauris Publishers, ] [ [http://www.usc.edu/dept/MSA/quran/017.qmt.html#017.106 Qur'an, Chapter 17, Verse 106] ]
*In Abhidharma, the number of anomalous generic types (of a possible 72) - e.g., events are considered "sui generis" because they are not reducible to either mind or matter - is 23.
*"Principia Discordia", the sacred text of Discordianism, holds that 23 (along with 5) is the sacred number of Eris, goddess of discord.

In sports

The number 23 has been retired for quite a few prominent athletes. Michael Jordan wore number 23 (with the exception of a short period of time) when he played professional basketball with the Chicago Bulls and, later, the Washington Wizards. Don Mattingly of the New York Yankees wore number 23; the New York Yankees retired the number in 1997. Ryne Sandberg, of the Chicago Cubs, wore number 23, which was retired on August 28, 2005. Bob Nystrom of the New York Islanders wore number 23 and has had the number retired in his honour.

Manchester City F.C. have not assigned the squad number 23 to any player since 2003. This is because Marc-Vivien Foé, the player who collapsed and died while playing for Cameroon on June 26 2003, had held this squad number at Manchester City.

23 is the highest number in Football World Cup squads.

In music

* The doorway David Bowie stands in on the Ziggy Stardust album is number 23.
* Several songs and albums use the number 23 as their titles, including Tristan Prettyman's debut album, the eleventh song from Tool's fourth full-length studio album "10,000 Days", "Viginti Tres" (Latin for twenty-three).
* Blonde Redhead have the album '23' and the song with the same name.
* Jimmy Eat World's song "23" appeared on their album Futures. The number also appears in the songs "Christmas Card" and "12.23.95" as well as on some items of clothing produced by the band.
* Four tet and Yellowcard both have songs titled "Twenty-Three".
* The song "Aquarius", by Boards of Canada, runs through a series of random spoken numbers which ends with the number twenty-three.
*On the album Enema of the State the song What's My Age Again? by Blink 182. There is a lyric that states "nobody likes you when you're 23"

In film and television

*"23" is a German film about Karl Koch
*"The Number 23" is a 2007 film starring Jim Carrey.
*23 is one of The Numbers - 4, 8, 15, 16, 23, and 42 - featured in "Lost".
*Mr. Hong-Tow a Japanese physiologist would often paint the number 23 on his body
*In The Matrix Reloaded, the Architect tells Neo it is of utmost importance to choose 23 people to repopulate Zion.
*In Jeepers Creepers, the Creeper appears every 23 years for 23 days to feast on human flesh.
*House number of psychologist played by Billy Crystal in Analyze That is 23.

In other fields

*In Zelda 64, twenty-three is number one.
*The 23 Enigma plays a prominent role in the plot of the Illuminatus! Trilogy by Robert Shea and Robert Anton Wilson.
*23 skidoo was a 20th Century American slang phrase.
*Dr Pepper is advertised as having 23 flavors.
*Julius Caesar was stabbed 23 times when he was assassinated.
*23 is the number of the French department Creuse

References

External links

* [http://www.mirror.co.uk/news/topstories/tm_objectid=13136269%26method=full%26siteid=94762-name_page.html Article in the British newspaper "The Mirror" regarding the power of the number 23]
* [http://nexus23.org A Portal for 23 Knowledge and Culture]
* [http://www.dauddegtre.co.uk/ 23 facts, 23 images, 23 gallery, and links to other 23's]