640807902 has 32 divisors (see below), whose sum is σ = 1627449600. Its totient is φ = 183087864.

The previous prime is 640807897. The next prime is 640807939. The reversal of 640807902 is 209708046.

640807902 is a `hidden beast` number, since 640 + 8 + 0 + 7 + 9 + 0 + 2 = 666.

It is a congruent number.

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, 847252 + ... + 848007.

It is an arithmetic number, because the mean of its divisors is an integer number (50857800).

Almost surely, 2^640807902 is an apocalyptic number.

640807902 is an abundant number, since it is smaller than the sum of its proper divisors (986641698).

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

640807902 is a wasteful number, since it uses less digits than its factorization.

640807902 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1695277 (or 1695271 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 640807902 is about 25314.1838106624. The cubic root of 640807902 is about 862.1363427224.

The spelling of 640807902 in words is "six hundred forty million, eight hundred seven thousand, nine hundred two".