640440264 has 64 divisors (see below), whose sum is σ = 1618344000. Its totient is φ = 211196160.

The previous prime is 640440233. The next prime is 640440331. The reversal of 640440264 is 462044046.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1646182 + ... + 1646570.

It is an arithmetic number, because the mean of its divisors is an integer number (25286625).

Almost surely, 2^640440264 is an apocalyptic number.

It is an amenable number.

640440264 is an abundant number, since it is smaller than the sum of its proper divisors (977903736).

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

640440264 is a wasteful number, since it uses less digits than its factorization.

640440264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 958 (or 954 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 30.

The square root of 640440264 is about 25306.9212667207. The cubic root of 640440264 is about 861.9714390581.

The spelling of 640440264 in words is "six hundred forty million, four hundred forty thousand, two hundred sixty-four".