23 (number)

23 (twenty-three) is the natural number following 22 and preceding 24. It is the smallest natural number with an eleven letter name in English.

Template:Numbers 20s
Cardinal	23 twenty-three
Ordinal	23rd twenty-third
Factorization	prime
Roman numeral	XXIII
Binary	10111
Octal	27
Hexadecimal	17

In mathematics

Twenty-three is the ninth prime number, the smallest odd prime that is not a twin prime. Twenty-three is also the fifth factorial prime, the second Woodall prime, and the second Smarandache-Wellin 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).

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.

A highly cototient number, 23 is the solution to x - φ(x) for the integers 95, 119, 143, 529.

The codewords in the perfect (non-extended) binary Golay code are of size 23.

In binary, 23 is the smallest prime having a composite sum of digits.

In science

• The atomic number of vanadium and the approximate atomic mass (in AMU) of sodium.
• The number of chromosomes in a human germline cell
• Humans have 23 pairs of chromosomes.

Astronomy

• Messier object M23, a magnitude 6.0 open cluster in the constellation Sagittarius

• The New General Catalogue object NGC 23, a magnitude 12.0 barred spiral galaxy in the constellation Pegasus

• The Saros number of the solar eclipse series which began on -2145 May 7 and ended on -865 June 15. The duration of Saros series 23 was 1280.1 years, and it contained 72 solar eclipses.

• The Saros number of the lunar eclipse series which began on -1843 February 14 and ended on -527 April 14. The duration of Saros series 23 was 1316.2 years, and it contained 74 lunar eclipses.

• The 23rd moon of Jupiter is Carme

In sports

• The squad number (or jersey number) of various athletes:
  • Don Mattingly's number when he played for the New York Yankees baseball team. It was retired on August 31, 1997.
  • Michael Jordan's jersey number, with the exception of a short period of time, when he played for the Chicago Bulls basketball team as well as the Washington Wizards. The number now has special significance throughout sports, especially in basketball. Many athletes wear the number 23 either as a tribute to Jordan or because they would like to "be like Mike." Two examples of this in football (soccer) are David Beckham and Sol Campbell both 23 at Real Madrid and Arsenal respectively .
  • David Beckham's squad number at Real Madrid football (soccer) club, inspired by the aforementioned Jordan.
  • Manchester City F.C. have not assigned the squad number 23 to any player since 2003. This is due to the fact that 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.
  • Chris Drury's jersey number for the Buffalo Sabres which is inspired by childhood hero Don Mattingly.
  • Ryne Sandberg's number when he played for the Chicago Cubs baseball team. It was retired on August 28, 2005.
  • December 28 - The Baltimore Colts beat The New York Giants 23-17 in overtime to win The NFL Championship. Occurred in 1958 ( 1+ 9 + 5 + 8 = 23 )
  • Michael Clarke's number in ODI cricket, passed on from Shane Warne in 2004 after Warnes retirement.
  • Lebron James's jersey number for the NBA's Cleveland Cavaliers.

Occult significance

See also: 23 (numerology).

• The sacred number (along with 5) of Eris, goddess of discord, according to the Principia Discordia; it is the number of the Illuminati.
• Like 13, sometimes considered lucky or otherwise significant (as in the occult writings of Aleister Crowley and William S. Burroughs); see the 23 enigma.
  • 23 Skidoo is a title of a poem in Aliester Crowley's book "The Book of Lies - Falsely so Called"
• Robert Anton Wilson's book, Cosmic Trigger I: Final Secret of the Illuminati, lists 23 as a cosmic number with strong connections to arcane magic and synchronicity. Numerous people have claimed to see 23's everywhere (the 23 curse) prior to enormous success and fruitfulness.
  • In many other of Wilson's works (especially The Illuminatus! Trilogy) 23 is given special importance. Many Discordians use this number for any number of purposes.
• 23rdian is a person who constantly witnesses the number 23 in high concentration.

In other fields

Twenty-three is:

• In early 20th century United States slang, it meant to leave a place. (From the phrase 23 skiddoo ; the origins of the phrase are largely unknown).
• Sydney Carton is the 23rd person executed at the end of A Tale of Two Cities, by Charles Dickens.
• 23, a German movie about Karl Koch.
• Viginti Tres (23 in Latin) is a song on the album 10,000 Days by Tool
• A telegraphers' code meaning "line break".
• When mathematician John Forbes Nash suffered from schizophrenic delusions, he said that Life Magazine had run a cover story of him disguised as Pope John XXIII as his name was John and his favorite prime number was 23. Nash published a total of 23 scientific articles.
• The actor Danny Trejo's name in "Con Air" was Johnny 23.
• The number of people (16 females, 7 males) Neo was to select in order to refound Zion in The Matrix Reloaded
• A song of the band Jimmy Eat World on their album Futures.
• ASCII character number 23 is ETB, end transmission block.
• The smallest group of people where there is more than a 50% chance that 2 people will share the same birth day (day and month, not year).
• One of the "Lost Numbers" on the television show, Lost, along with 4, 8, 15, 16 and 42. According to producers of the show, 23 is the most important of these six numbers.
• Purple 23 is the parking space where Kramer hides his air conditioner in the Seinfeld season 3 episode "The Parking Garage"
• Psalm 23 of the Bible is possibly the most quoted and best known psalm.
• The standard TCP/IP port number for Telnet connections.
• The number of crosses on the hill at the end of the Monty Python film "The Life of Brian" is 23.
• Princess Leia is being held in detention block AA-23 in the Star Wars film "A New Hope".
• When Zoidberg upsets the shelf containing the various alternative universes in the Futurama episode "The Farnsworth Parabox", the only visible universe number is 23.
• In William Shakespeare's Julius Caesar, Caesar was stabbed a total 23 times.
• Number 23 is recognized as a number of Freetekno culture - often used on decorations, party names, etc.
• In the movie Serendipity during the beginning of the movie, the 23rd floor is the floor both John and Sarah pick before "the devil" separates them.
• 2005 December 23 - Azerbaijan Airlines Flight 217 from Baku, Azerbaijan to Aktau, Kazakhstan crashed shortly after takeoff killing 23 people.

Miscellaneous

Jim Carrey, in People Magazine, April 17, 2006, page 142, is quoted as saying: "I've [been fixated on] the number 23 for years. It's everywhere. Each parent passes on 23 chromosomes; Earth's axis is at a 23° angle. Psalm 23 is my mantra..."