646636404 has 24 divisors (see below), whose sum is σ = 1510161408. Its totient is φ = 215353600.

The previous prime is 646636391. The next prime is 646636427. The reversal of 646636404 is 404636646.

646636404 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

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, 9597 + ... + 37220.

It is an arithmetic number, because the mean of its divisors is an integer number (62923392).

Almost surely, 2^646636404 is an apocalyptic number.

It is an amenable number.

646636404 is an abundant number, since it is smaller than the sum of its proper divisors (863525004).

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

646636404 is a wasteful number, since it uses less digits than its factorization.

646636404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47975 (or 47973 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 39.

The square root of 646636404 is about 25429.0464626576. The cubic root of 646636404 is about 864.7423264929.

The spelling of 646636404 in words is "six hundred forty-six million, six hundred thirty-six thousand, four hundred four".