640739244 has 24 divisors (see below), whose sum is σ = 1560061440. Its totient is φ = 204293584.

The previous prime is 640739227. The next prime is 640739321. The reversal of 640739244 is 442937046.

640739244 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, 1160484 + ... + 1161035.

It is an arithmetic number, because the mean of its divisors is an integer number (65002560).

Almost surely, 2^640739244 is an apocalyptic number.

It is an amenable number.

640739244 is an abundant number, since it is smaller than the sum of its proper divisors (919322196).

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

640739244 is a wasteful number, since it uses less digits than its factorization.

640739244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2321549 (or 2321547 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 39.

The square root of 640739244 is about 25312.8276571386. The cubic root of 640739244 is about 862.1055510343.

The spelling of 640739244 in words is "six hundred forty million, seven hundred thirty-nine thousand, two hundred forty-four".