22 (twenty-two) is the natural number following 21 and preceding 23. In a 24-hour clock, the twenty-second hour is in conventional language called ten or ten o'clock.
22 is deficient
22 is an even composite number; its proper divisors are 1, 2, and 11.
22 is the sixth discrete semiprime and the fourth in the (2 × q) family. With 21 it forms the second discrete semiprime pair.
22 has an aliquot sum of 14 and is the fifth composite number found in the 7-aliquot tree. It has a 7-member aliquot sequence 22, 14, 10, 8, 7, 1, 0 of which the next two members are themselves discrete semiprimes, 22 is the first discrete semiprime exhibiting this property. 169 also has 14 as its aliquot sum. 22 is itself the aliquot sum of two numbers 20, 38.
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 (see lazy caterer's sequence).
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 π, 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.
In physics and chemistry
22 is the atomic number of titanium.
22 is the designation of the USAF stealth fighter, the F-22 Raptor.
"Twenty Two" (Millencolin song) 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.
Iron Maiden has a song named "22 Acacia Avenue".
Death Metal band Hypocrisy album "Catch 22" released in year 2002.
Lily Allen has a song titled "22" from her album It's Not Me, It's You.
Paul Weller has a song and album named 22 Dreams. The album contains 22 songs on it, including the song "22 Dreams".
The Norwegian electronica project Ugress uses 22 as a recurring theme. All four albums features a track with 22 in the title.
Taylor Swift has a song from her fourth album Red titled "22".
Ashbury Heights has a song titled "The Number 22" from album The Looking Glass Society.
In bingo, 22 is referred to as "Two Little Ducks"
Catch-22 (1961), Joseph Heller's novel, and its 1970 film version) by Joseph Heller, 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" (February 10, 1961) is Season 2–episode 17 (February 10, 1961) 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
A quotation mark (in a URL it appears as a "%22")
There are 22 letters in the Hebrew alphabet.
In the Kabbalah, there are 22 paths between the Sephirot.
22 is the number of players on the field at any one time in an American football match
Each team is allowed a squad of 22 players (18 on the field and 4 interchanges).
In the top-level Australian Football League, each team plays 22 matches in the regular (or "home-and-away") season.
The length of a cricket pitch is 22 yards.
The jersey number 22 has been retired by several North American sports teams in honor of past playing greats:
In Major League Baseball:
The Baltimore Orioles, for Hall of Famer Jim Palmer.
In the NBA:
The Boston Celtics, for Hall of Famer Ed Macauley.
The Cleveland Cavaliers, for Larry Nance.
The Dallas Mavericks, for Rolando Blackman.
The Houston Rockets and Portland Trail Blazers, both for Hall of Famer Clyde Drexler.
The Los Angeles Lakers, for Hall of Famer Elgin Baylor.
The Lakers have separately honored #22 for Hall of Famer Slater Martin, who wore the number before Baylor when the team was the Minneapolis Lakers.
The New York Knicks, for Hall of Famer Dave DeBusschere.
In the NFL:
The Baltimore Colts retired #22 for Buddy Young. Since the team's controversial relocation to Indianapolis, the current Indianapolis Colts have not retired any numbers, but continue to honor all numbers retired by the franchise in Baltimore.
The Detroit Lions, for Hall of Famer Bobby Layne.
The Dallas Cowboys have a policy of not retiring numbers. However, the team has not issued #22 since Hall of Famer Emmitt Smith left the team in 2002.
In the NHL:
The New York Islanders, for Hall of Famer Mike Bossy.
"22" is the number of a car in NASCAR's Sprint Cup Series currently owned by Penske Racing. Joey Logano has the Sprint Cup ride in 2014.
"22" Is the number of AMA Supercross rider Chad Reed, winning 4 AMA FIM World Champion Titles.
"22" was the number of Lewis Hamilton's McLaren-Mercedes in 2008 and is the number of Jenson Button's Brawn-Mercedes in 2009, both winning the drivers' championship that year.
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.
22 is the number of players on the field in a football (soccer) match
In weights and measures
The number of yards in a chain.
Twenty-two may also refer to:
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 (typically "22, v'là les flics !" (In English: "5-0! Cops!")
In photography, f/22 is the largest f-stop (and thus smallest aperture) available on most lenses made for single-lens reflex cameras
