640556585 has 16 divisors (see below), whose sum is σ = 782161920. Its totient is φ = 503521920.

The previous prime is 640556563. The next prime is 640556591. The reversal of 640556585 is 585655046.

It is not a de Polignac number, because 640556585 - 2¹² = 640552489 is a prime.

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, 68120 + ... + 76950.

It is an arithmetic number, because the mean of its divisors is an integer number (48885120).

Almost surely, 2^640556585 is an apocalyptic number.

It is an amenable number.

640556585 is a deficient number, since it is larger than the sum of its proper divisors (141605335).

640556585 is a wasteful number, since it uses less digits than its factorization.

640556585 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9088.

The product of its (nonzero) digits is 720000, while the sum is 44.

The square root of 640556585 is about 25309.2193676534. The cubic root of 640556585 is about 862.0236215518.

The spelling of 640556585 in words is "six hundred forty million, five hundred fifty-six thousand, five hundred eighty-five".