640564408 has 32 divisors (see below), whose sum is σ = 1352517120. Its totient is φ = 281772000.

The previous prime is 640564399. The next prime is 640564411. The reversal of 640564408 is 804465046.

640564408 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 114678 + ... + 120133.

It is an arithmetic number, because the mean of its divisors is an integer number (42266160).

Almost surely, 2^640564408 is an apocalyptic number.

It is an amenable number.

640564408 is an abundant number, since it is smaller than the sum of its proper divisors (711952712).

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

640564408 is a wasteful number, since it uses less digits than its factorization.

640564408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 234859 (or 234855 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 37.

The square root of 640564408 is about 25309.3739156068. The cubic root of 640564408 is about 862.0271307830.

The spelling of 640564408 in words is "six hundred forty million, five hundred sixty-four thousand, four hundred eight".