640556424 has 80 divisors (see below), whose sum is σ = 1888616400. Its totient is φ = 202277088.

The previous prime is 640556387. The next prime is 640556431. The reversal of 640556424 is 424655046.

640556424 is a `hidden beast` number, since 6 + 4 + 0 + 5 + 5 + 642 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

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 19 ways as a sum of consecutive naturals, for example, 13702 + ... + 38325.

It is an arithmetic number, because the mean of its divisors is an integer number (23607705).

Almost surely, 2^640556424 is an apocalyptic number.

It is an amenable number.

640556424 is an abundant number, since it is smaller than the sum of its proper divisors (1248059976).

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

640556424 is a wasteful number, since it uses less digits than its factorization.

640556424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52064 (or 52051 counting only the distinct ones).

The product of its (nonzero) digits is 115200, while the sum is 36.

The square root of 640556424 is about 25309.2161869940. The cubic root of 640556424 is about 862.0235493304.

The spelling of 640556424 in words is "six hundred forty million, five hundred fifty-six thousand, four hundred twenty-four".