52 is the natural number following 51 and preceding 53.

Cardinal	fifty-two
Ordinal	52nd (fifty-second)
Factorization
Divisors	2, 4, 13, 26
Roman numeral	LII
Binary	110100
Hexadecimal	34

In mathematics

Fifty-two is the 5th Bell number and a decagonal number. It is an untouchable number, since it is never the sum of proper divisors of any number, and it is a noncototient since it is never the answer to the equation x - φ(x).

In astronomy

• Messier object M52, a magnitude 8.0 open cluster in the constellation Cassiopea , also known as
• The New General Catalogue object NGC 52 , a spiral galaxy in the constellation Pegasus
• The Saros number of the solar eclipse series which began on -1378 August 14 and ended on 155 February 19. The duration of Saros series 52 was 1532.5 years, and it contained 86 solar eclipses. The Saros number of the lunar eclipse series which began on -1026 May 27 and ended on 204 June 29. The duration of Saros series 52 was 1280.1 years, and it contained 72 lunar eclipses.

In other fields

The piano has 52 white keys

Fifty-two is also:

• The atomic number of tellurium
• The number of weeks in a year.
• The number of sons of Nebo in the Census of men of Israel upon return from exile (Holy Bible, Ezra 2:29).
• On the piano, the number of white keys (notes in the C major scale).
• The number of cards in a standard deck of playing cards, not counting Jokers or advertisement cards.
• The name of a practical joke card game 52 Pick-up.
• The code for international direct dial phone calls to Mexico.
• The year AD 52, 52 BC, and 1952.