640437257790 has 96 divisors (see below), whose sum is σ = 1923366702816. Its totient is φ = 146124718080.

The previous prime is 640437257783. The next prime is 640437257809. The reversal of 640437257790 is 97752734046.

640437257790 is a `hidden beast` number, since 64 + 0 + 4 + 3 + 7 + 2 + 577 + 9 + 0 = 666.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 19009827 + ... + 19043486.

It is an arithmetic number, because the mean of its divisors is an integer number (20035069821).

Almost surely, 2^640437257790 is an apocalyptic number.

640437257790 is an abundant number, since it is smaller than the sum of its proper divisors (1282929445026).

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

640437257790 is a wasteful number, since it uses less digits than its factorization.

640437257790 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38053354 (or 38053351 counting only the distinct ones).

The product of its (nonzero) digits is 8890560, while the sum is 54.

The spelling of 640437257790 in words is "six hundred forty billion, four hundred thirty-seven million, two hundred fifty-seven thousand, seven hundred ninety".