645964256 has 36 divisors (see below), whose sum is σ = 1479377088. Its totient is φ = 276841152.

The previous prime is 645964247. The next prime is 645964301. The reversal of 645964256 is 652469546.

It is a self number, because there is not a number n which added to its sum of digits gives 645964256.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 204416 + ... + 207551.

It is an arithmetic number, because the mean of its divisors is an integer number (41093808).

Almost surely, 2^645964256 is an apocalyptic number.

It is an amenable number.

645964256 is an abundant number, since it is smaller than the sum of its proper divisors (833412832).

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

645964256 is a wasteful number, since it uses less digits than its factorization.

645964256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 411991 (or 411976 counting only the distinct ones).

The product of its digits is 1555200, while the sum is 47.

The square root of 645964256 is about 25415.8268801155. The cubic root of 645964256 is about 864.4426030178.

The spelling of 645964256 in words is "six hundred forty-five million, nine hundred sixty-four thousand, two hundred fifty-six".