638123825 has 12 divisors (see below), whose sum is σ = 791980188. Its totient is φ = 510043200.

The previous prime is 638123767. The next prime is 638123839. The reversal of 638123825 is 528321836.

638123825 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 6 ways, for example, as 138109504 + 500014321 = 11752^2 + 22361^2 .

It is not a de Polignac number, because 638123825 - 2²⁰ = 637075249 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 18719 + ... + 40331.

It is an arithmetic number, because the mean of its divisors is an integer number (65998349).

Almost surely, 2^638123825 is an apocalyptic number.

It is an amenable number.

638123825 is a deficient number, since it is larger than the sum of its proper divisors (153856363).

638123825 is a wasteful number, since it uses less digits than its factorization.

638123825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22804 (or 22799 counting only the distinct ones).

The product of its digits is 69120, while the sum is 38.

The square root of 638123825 is about 25261.1129010580. The cubic root of 638123825 is about 860.9309483495.

The spelling of 638123825 in words is "six hundred thirty-eight million, one hundred twenty-three thousand, eight hundred twenty-five".