64521657 has 16 divisors (see below), whose sum is σ = 96290880. Its totient is φ = 42698016.

The previous prime is 64521641. The next prime is 64521671. The reversal of 64521657 is 75612546.

It is a happy number.

64521657 is a `hidden beast` number, since 645 + 2 + 1 + 6 + 5 + 7 = 666.

It is not a de Polignac number, because 64521657 - 2⁴ = 64521641 is a prime.

It is not an unprimeable number, because it can be changed into a prime (64521697) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5023 + ... + 12420.

It is an arithmetic number, because the mean of its divisors is an integer number (6018180).

Almost surely, 2^64521657 is an apocalyptic number.

It is an amenable number.

64521657 is a deficient number, since it is larger than the sum of its proper divisors (31769223).

64521657 is a wasteful number, since it uses less digits than its factorization.

64521657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17589 (or 17583 counting only the distinct ones).

The product of its digits is 50400, while the sum is 36.

The square root of 64521657 is about 8032.5373948709. The cubic root of 64521657 is about 401.0838459590.

The spelling of 64521657 in words is "sixty-four million, five hundred twenty-one thousand, six hundred fifty-seven".