# 52 (number)

 ← 51 52 53 →
Cardinalfifty-two
Ordinal52nd
(fifty-second)
Factorization22 × 13
Divisors1, 2, 4, 13, 26, 52
Greek numeralΝΒ´
Roman numeralLII
Binary1101002
Ternary12213
Quaternary3104
Quinary2025
Senary1246
Octal648
Duodecimal4412
Vigesimal2C20
Base 361G36

52 (fifty-two) is the natural number following 51 and preceding 53.

## In mathematics

Fifty-two is the 6th Bell number[1] and a decagonal number.[2] It is an untouchable number, since it is never the sum of proper divisors of any number,[3] and it is a noncototient since it is never the answer to the equation x − φ(x).[4]

## In other fields

The piano has 52 white keys

Fifty-two is:

## Historical years

52 BC, AD 52, 1052, 1952, 2052, etc.

## References

1. ^ "Sloane's A000110 : Bell or exponential numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-30.
2. ^ "Sloane's A001107 : 10-gonal (or decagonal) numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-30.
3. ^ "Sloane's A005114 : Untouchable numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-30.
4. ^ "Sloane's A005278 : Noncototients". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-30.