634317021 has 16 divisors (see below), whose sum is σ = 1012016320. Its totient is φ = 390348720.

The previous prime is 634317007. The next prime is 634317031. The reversal of 634317021 is 120713436.

634317021 is a `hidden beast` number, since 634 + 3 + 1 + 7 + 0 + 21 = 666.

It is not a de Polignac number, because 634317021 - 2⁹ = 634316509 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (634317001) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 903235 + ... + 903936.

It is an arithmetic number, because the mean of its divisors is an integer number (63251020).

Almost surely, 2^634317021 is an apocalyptic number.

It is an amenable number.

634317021 is a deficient number, since it is larger than the sum of its proper divisors (377699299).

634317021 is a wasteful number, since it uses less digits than its factorization.

634317021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1807193 (or 1807187 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 27.

The square root of 634317021 is about 25185.6510934302. The cubic root of 634317021 is about 859.2155371359.

The spelling of 634317021 in words is "six hundred thirty-four million, three hundred seventeen thousand, twenty-one".