51643664 has 20 divisors (see below), whose sum is σ = 103510860. Its totient is φ = 24931200.

The previous prime is 51643651. The next prime is 51643681. The reversal of 51643664 is 46634615.

It can be written as a sum of positive squares in 2 ways, for example, as 38539264 + 13104400 = 6208^2 + 3620^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55187 + ... + 56114.

It is an arithmetic number, because the mean of its divisors is an integer number (5175543).

Almost surely, 2^51643664 is an apocalyptic number.

It is an amenable number.

51643664 is an abundant number, since it is smaller than the sum of its proper divisors (51867196).

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

51643664 is a wasteful number, since it uses less digits than its factorization.

51643664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111338 (or 111332 counting only the distinct ones).

The product of its digits is 51840, while the sum is 35.

The square root of 51643664 is about 7186.3526214624. The cubic root of 51643664 is about 372.3965786487.

The spelling of 51643664 in words is "fifty-one million, six hundred forty-three thousand, six hundred sixty-four".