640812662500 has 72 divisors (see below), whose sum is σ = 1484140712040. Its totient is φ = 241247040000.

The previous prime is 640812662459. The next prime is 640812662521. The reversal of 640812662500 is 5266218046.

It can be written as a sum of positive squares in 12 ways, for example, as 633004819456 + 7807843044 = 795616^2 + 88362^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1295295 + ... + 1720294.

It is an arithmetic number, because the mean of its divisors is an integer number (20613065445).

Almost surely, 2^640812662500 is an apocalyptic number.

It is an amenable number.

640812662500 is an abundant number, since it is smaller than the sum of its proper divisors (843328049540).

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

640812662500 is a wasteful number, since it uses less digits than its factorization.

640812662500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3015635 (or 3015613 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 40.

The spelling of 640812662500 in words is "six hundred forty billion, eight hundred twelve million, six hundred sixty-two thousand, five hundred".