640515264 has 28 divisors (see below), whose sum is σ = 1694697144. Its totient is φ = 213505024.

The previous prime is 640515259. The next prime is 640515277. The reversal of 640515264 is 462515046.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1667817 + ... + 1668200.

It is an arithmetic number, because the mean of its divisors is an integer number (60524898).

Almost surely, 2^640515264 is an apocalyptic number.

640515264 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

640515264 is an abundant number, since it is smaller than the sum of its proper divisors (1054181880).

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

640515264 is a wasteful number, since it uses less digits than its factorization.

640515264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3336032 (or 3336022 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 33.

The square root of 640515264 is about 25308.4030314044. The cubic root of 640515264 is about 862.0050853575.

The spelling of 640515264 in words is "six hundred forty million, five hundred fifteen thousand, two hundred sixty-four".