640392404 has 12 divisors (see below), whose sum is σ = 1169412384. Its totient is φ = 306274584.

The previous prime is 640392391. The next prime is 640392409. The reversal of 640392404 is 404293046.

640392404 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×640392404² = 820204862201798432, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640392409) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3480302 + ... + 3480485.

It is an arithmetic number, because the mean of its divisors is an integer number (97451032).

Almost surely, 2^640392404 is an apocalyptic number.

It is an amenable number.

640392404 is a deficient number, since it is larger than the sum of its proper divisors (529019980).

640392404 is a wasteful number, since it uses less digits than its factorization.

640392404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6960814 (or 6960812 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 32.

The square root of 640392404 is about 25305.9756579350. The cubic root of 640392404 is about 861.9499668600.

The spelling of 640392404 in words is "six hundred forty million, three hundred ninety-two thousand, four hundred four".