640804648 has 32 divisors (see below), whose sum is σ = 1355940000. Its totient is φ = 281229760.

The previous prime is 640804639. The next prime is 640804651. The reversal of 640804648 is 846408046.

It is a self number, because there is not a number n which added to its sum of digits gives 640804648.

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, 122998 + ... + 128101.

It is an arithmetic number, because the mean of its divisors is an integer number (42373125).

Almost surely, 2^640804648 is an apocalyptic number.

It is an amenable number.

640804648 is an abundant number, since it is smaller than the sum of its proper divisors (715135352).

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

640804648 is a wasteful number, since it uses less digits than its factorization.

640804648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 251145 (or 251141 counting only the distinct ones).

The product of its (nonzero) digits is 147456, while the sum is 40.

The square root of 640804648 is about 25314.1195383130. The cubic root of 640804648 is about 862.1348834206.

The spelling of 640804648 in words is "six hundred forty million, eight hundred four thousand, six hundred forty-eight".