640991209584 has 40 divisors (see below), whose sum is σ = 1806429773952. Its totient is φ = 194239760320.

The previous prime is 640991209577. The next prime is 640991209597. The reversal of 640991209584 is 485902199046.

It is a congruent number.

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, 606998724 + ... + 606999779.

Almost surely, 2^640991209584 is an apocalyptic number.

It is an amenable number.

640991209584 is an abundant number, since it is smaller than the sum of its proper divisors (1165438564368).

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

640991209584 is a wasteful number, since it uses less digits than its factorization.

640991209584 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1213998525 (or 1213998519 counting only the distinct ones).

The product of its (nonzero) digits is 5598720, while the sum is 57.

The spelling of 640991209584 in words is "six hundred forty billion, nine hundred ninety-one million, two hundred nine thousand, five hundred eighty-four".