52 (number) explained
Number: | 52 |
Divisor: | 1, 2, 4, 13, 26, 52 |
52 (fifty-two) is the natural number following 51 and preceding 53.
In mathematics
Fifty-two is
- a composite number; a square-prime, of the form (p2, q) where q is a higher prime. It is the sixth of this form and the fifth of the form (22.q).
- the 5th Bell number,[1] the number of ways to partition a set of 5 objects.
- a decagonal number.[2]
- with an aliquot sum of 46; within an aliquot sequence of seven composite numbers (52,46,26,16,15, 9,4,3,1,0) to the prime in the 3-aliquot tree. This sequence does not extend above 52 because 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 not equal to x − φ(x) for any x.[4]
- a vertically symmetrical number.[5]
In science
Astronomy
In other fields
Fifty-two is:
Historical years
52 BC, AD 52, 1052, 1952 etc.
See also
Notes and References
- Web site: Sloane's A000110 : Bell or exponential numbers. The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. 2016-05-30.
- Web site: Sloane's A001107 : 10-gonal (or decagonal) numbers. The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. 2016-05-30.
- Web site: Sloane's A005114 : Untouchable numbers. The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. 2016-05-30.
- Web site: Sloane's A005278 : Noncototients. The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. 2016-05-30.
- Web site: Sloane's A053701 : Vertically symmetric numbers. The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. 2022-05-08.