640217564 has 12 divisors (see below), whose sum is σ = 1280435184. Its totient is φ = 274378944.

The previous prime is 640217561. The next prime is 640217587. The reversal of 640217564 is 465712046.

640217564 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

640217564 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640217561) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11432429 + ... + 11432484.

It is an arithmetic number, because the mean of its divisors is an integer number (106702932).

Almost surely, 2^640217564 is an apocalyptic number.

It is an amenable number.

640217564 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

640217564 is a wasteful number, since it uses less digits than its factorization.

640217564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22864924 (or 22864922 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 35.

The square root of 640217564 is about 25302.5209020761. The cubic root of 640217564 is about 861.8715164972.

The spelling of 640217564 in words is "six hundred forty million, two hundred seventeen thousand, five hundred sixty-four".