643893904 has 40 divisors (see below), whose sum is σ = 1343351520. Its totient is φ = 297865728.

The previous prime is 643893883. The next prime is 643893917. The reversal of 643893904 is 409398346.

It is a super-2 number, since 2×643893904² = 829198719216722432, which contains 22 as substring.

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, 4014 + ... + 36109.

It is an arithmetic number, because the mean of its divisors is an integer number (33583788).

Almost surely, 2^643893904 is an apocalyptic number.

It is an amenable number.

643893904 is an abundant number, since it is smaller than the sum of its proper divisors (699457616).

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

643893904 is a wasteful number, since it uses less digits than its factorization.

643893904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40207 (or 40201 counting only the distinct ones).

The product of its (nonzero) digits is 559872, while the sum is 46.

The square root of 643893904 is about 25375.0646107552. The cubic root of 643893904 is about 863.5180854470.

The spelling of 643893904 in words is "six hundred forty-three million, eight hundred ninety-three thousand, nine hundred four".