22 (number)

In mathematics

• 22 is a deficient number.
• 22 is an even composite number and a semiprime; its proper divisors are 1, 2, and 11.
• 22 is a pentagonal number and a centered heptagonal number.
• When cutting a circle with just six line segments, the maximum number of pieces that can be so created is 22, thus 22 is a central polygonal number.
• 22 is the number of partitions of 8.
• 22 is the sum of the totient function for the first eight integers.
• 22 is a Perrin number, preceded in the sequence by 10, 12, and 17.
• 22 divided by 7 approximates the irrational number Pi|, the ratio of the circumference of a circle to its diameter.
• 22 is an Erdős–Woods number, since it is possible to find sequences of 22 consecutive integers such that each inner member shares a factor with either the first or the last member.
• 22 is a Smith number in base 10.
• "2-2" is the only fixed point of John Conway's look-and-say function.

  In physics and chemistry

• 22 is the atomic number of titanium.

  In aircraft

• 22 is the designation of the USAF stealth fighter, the F-22 Raptor.

  In art, entertainment, and media

In music

• "Twenty Two" is a 1997 song by the punk band Millencolin
• In Jay-Z's song "22 Two's", he rhymes the words: too, to, and two, 22 times in the first verse.
• "22 Acacia Avenue" is a song by Iron Maiden on the album The Number of the Beast
• Catch 22 is an album by death metal band Hypocrisy
• "22" is a song by Lily Allen on the album It's Not Me, It's You.
• 22 Dreams is a song and album by Paul Weller. The album contains 22 songs on it.
• The Norwegian electronica project Ugress uses 22 as a recurring theme. All four albums feature a track with 22 in the title.
• "22" is a song by Taylor Swift on her fourth album Red
• "The Number 22" is a song by Ashbury Heights on the album The Looking Glass Society.
• 22, A Million is an album by Bon Iver. The first track of the album is called "22 ".
• Cubic 22 was a Belgian techno duo.
• "22" is a song by the English alternative rock band Deaf Havana on their album Old Souls
• "22" is a song by the Irish singer Sarah McTernan. She will represent Ireland with this song in Eurovision 2019.

  In other fields

• Catch-22, Joseph Heller's novel, and its 1970 film adaptation gave rise to the expression of logic "catch-22".
• Revista 22 is a magazine published in Romania.
• There are 22 stars in the Paramount Pictures logo.
• "Twenty Two" is Season 2-episode 17 of the 1959-64 TV series The Twilight Zone, in which a hospitalized dancer has nightmares about a sinister nurse inviting her to Room 22, the hospital morgue.
• Traditional Tarot decks have 22 cards with allegorical subjects. These serve as trump cards in the game. The Fool is usually a kind of wild-card among the trumps and unnumbered, so the highest trump is numbered 21. Occult Tarot decks usually have 22 similar cards which are called Major Arcana by fortune-tellers. Occultists have related this number to the 22 letters of the Hebrew alphabet and the 22 paths in the Kabbalistic Tree of Life.

  In computing and technology

• 22 is the standard port number for the Secure Shell protocol

  In religion

• There are 22 letters in the Hebrew alphabet.
• In the Kabbalah, there are 22 paths between the Sephirot.

  In sports

• In both American football and association football, a total of 22 players start the game, and this is also the maximum number of players that can be legally involved in play at any given time.
• In Australian rules football, each team is allowed a squad of 22 players.
• The length of a cricket pitch is 22 yards.
• In rugby union, the "22" is a line in each half of the field which is 22 meters from the respective try line. It has significance in a number of laws particularly relating to kicking the ball away.
• A snooker game starts with 22 coloured balls at specified locations on the table.

  In weights and measures

• The number of yards in a chain.

  In other uses

• 22 is the number of the French department Côtes-d'Armor
• "22" is a common name for the.22 calibre.22 Long Rifle cartridge.
• In French jargon, "22" is used as a phrase to warn of the coming of the police
• In photography, f/22 is the largest f-stop available on most lenses made for single-lens reflex cameras
• The total number of cases on Deal or No Deal