51660 has 72 divisors (see below), whose sum is σ = 183456. Its totient is φ = 11520.

The previous prime is 51659. The next prime is 51673. The reversal of 51660 is 6615.

51660 is a `hidden beast` number, since 5 + 1 + 660 = 666.

51660 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nialpdrome in base 9.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1240 + ... + 1280.

It is an arithmetic number, because the mean of its divisors is an integer number (2548).

2⁵¹⁶⁶⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (91728).

51660 is an abundant number, since it is smaller than the sum of its proper divisors (131796).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51660 is a wasteful number, since it uses less digits than its factorization.

51660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63 (or 58 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 18.

The square root of 51660 is about 227.2883630985. The cubic root of 51660 is about 37.2435840188.

It can be divided in two parts, 516 and 60, that added together give a square (576 = 24²).

The spelling of 51660 in words is "fifty-one thousand, six hundred sixty".