640538368 has 36 divisors (see below), whose sum is σ = 1319835328. Its totient is φ = 309934080.

The previous prime is 640538351. The next prime is 640538383. The reversal of 640538368 is 863835046.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32421 + ... + 48292.

Almost surely, 2^640538368 is an apocalyptic number.

It is an amenable number.

640538368 is an abundant number, since it is smaller than the sum of its proper divisors (679296960).

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

640538368 is an equidigital number, since it uses as much as digits as its factorization.

640538368 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80760 (or 80746 counting only the distinct ones).

The product of its (nonzero) digits is 414720, while the sum is 43.

The square root of 640538368 is about 25308.8594764758. The cubic root of 640538368 is about 862.0154496830.

The spelling of 640538368 in words is "six hundred forty million, five hundred thirty-eight thousand, three hundred sixty-eight".