51 may refer to:
*
51 (number)
51 (fifty-one) is the natural number following 50 and preceding 52.
In mathematics
Fifty-one is
* a pentagonal number as well as a centered pentagonal number and an 18-gonal number
*the 6th Motzkin number, telling the number of ways to dra ...
* The year
**
51 BC
**
AD 51
AD 51 (Roman numerals, LI) was a common year starting on Friday of the Julian calendar. At the time, it was known as the Year of the Consulship of Claudius, Caesar and Servius Cornelius Scipio Salvidienus Orfitus (consul 51), Scipio (or, less fr ...
**
1951
Events
January
* January 4 – Korean War: Third Battle of Seoul – Chinese and North Korean forces capture Seoul for the second time (having lost the Second Battle of Seoul in September 1950).
* January 9 – The Government of the Uni ...
**
2051
*
''51'' (film), a 2011 American horror film directed by Jason Connery
* "
Fifty-One", an episode of the American television drama series ''Breaking Bad''
*
''51'' (album), a 2012 mixtape by rapper Kool A.D.
* "Fifty One", a song by Karma to Burn from the album ''
V'', 2011
*
51 Nemausa, a main-belt asteroid
{{Numberdis