656643645 has 64 divisors (see below), whose sum is σ = 1344000000. Its totient is φ = 297960768.

The previous prime is 656643641. The next prime is 656643653. The reversal of 656643645 is 546346656.

656643645 is a `hidden beast` number, since 6 + 566 + 43 + 6 + 45 = 666.

It is not a de Polignac number, because 656643645 - 2² = 656643641 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 656643645.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (656643641) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 128856 + ... + 133854.

It is an arithmetic number, because the mean of its divisors is an integer number (21000000).

Almost surely, 2^656643645 is an apocalyptic number.

It is an amenable number.

656643645 is an abundant number, since it is smaller than the sum of its proper divisors (687356355).

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

656643645 is a wasteful number, since it uses less digits than its factorization.

656643645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5159 (or 5153 counting only the distinct ones).

The product of its digits is 1555200, while the sum is 45.

The square root of 656643645 is about 25625.0589267615. The cubic root of 656643645 is about 869.1803814767.

The spelling of 656643645 in words is "six hundred fifty-six million, six hundred forty-three thousand, six hundred forty-five".