640242928 has 40 divisors (see below), whose sum is σ = 1338101856. Its totient is φ = 295008000.

The previous prime is 640242919. The next prime is 640242961. The reversal of 640242928 is 829242046.

It is a super-2 number, since 2×640242928² = 819822013708026368, which contains 22 as substring.

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

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, 143613 + ... + 148003.

Almost surely, 2^640242928 is an apocalyptic number.

It is an amenable number.

640242928 is an abundant number, since it is smaller than the sum of its proper divisors (697858928).

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

640242928 is a wasteful number, since it uses less digits than its factorization.

640242928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5113 (or 5107 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 37.

The square root of 640242928 is about 25303.0221119929. The cubic root of 640242928 is about 861.8828981596.

The spelling of 640242928 in words is "six hundred forty million, two hundred forty-two thousand, nine hundred twenty-eight".