640440352 has 24 divisors (see below), whose sum is σ = 1261560636. Its totient is φ = 320044032.

The previous prime is 640440349. The next prime is 640440397. The reversal of 640440352 is 253044046.

It can be written as a sum of positive squares in 2 ways, for example, as 587383696 + 53056656 = 24236^2 + 7284^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 640440352.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 69148 + ... + 77860.

Almost surely, 2^640440352 is an apocalyptic number.

It is an amenable number.

640440352 is a deficient number, since it is larger than the sum of its proper divisors (621120284).

640440352 is a wasteful number, since it uses less digits than its factorization.

640440352 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11020 (or 11012 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 28.

The square root of 640440352 is about 25306.9230053754. The cubic root of 640440352 is about 861.9714785380.

Adding to 640440352 its reverse (253044046), we get a palindrome (893484398).

The spelling of 640440352 in words is "six hundred forty million, four hundred forty thousand, three hundred fifty-two".