640297518 has 16 divisors (see below), whose sum is σ = 1463537280. Its totient is φ = 182942136.

The previous prime is 640297507. The next prime is 640297547. The reversal of 640297518 is 815792046.

It is a Harshad number since it is a multiple of its sum of digits (42), and also a Moran number because the ratio is a prime number: 15245179 = 640297518 / (6 + 4 + 0 + 2 + 9 + 7 + 5 + 1 + 8).

It is a self number, because there is not a number n which added to its sum of digits gives 640297518.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7622548 + ... + 7622631.

It is an arithmetic number, because the mean of its divisors is an integer number (91471080).

Almost surely, 2^640297518 is an apocalyptic number.

640297518 is an abundant number, since it is smaller than the sum of its proper divisors (823239762).

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

640297518 is a wasteful number, since it uses less digits than its factorization.

640297518 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15245191.

The product of its (nonzero) digits is 120960, while the sum is 42.

The square root of 640297518 is about 25304.1008138997. The cubic root of 640297518 is about 861.9073934712.

The spelling of 640297518 in words is "six hundred forty million, two hundred ninety-seven thousand, five hundred eighteen".