640805704 has 64 divisors (see below), whose sum is σ = 1576857600. Its totient is φ = 236520000.

The previous prime is 640805677. The next prime is 640805719. The reversal of 640805704 is 407508046.

It is a self number, because there is not a number n which added to its sum of digits gives 640805704.

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, 15672 + ... + 39079.

It is an arithmetic number, because the mean of its divisors is an integer number (24638400).

Almost surely, 2^640805704 is an apocalyptic number.

It is an amenable number.

640805704 is an abundant number, since it is smaller than the sum of its proper divisors (936051896).

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

640805704 is a wasteful number, since it uses less digits than its factorization.

640805704 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54794 (or 54790 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 34.

The square root of 640805704 is about 25314.1403962291. The cubic root of 640805704 is about 862.1353569991.

The spelling of 640805704 in words is "six hundred forty million, eight hundred five thousand, seven hundred four".