638138125 has 20 divisors (see below), whose sum is σ = 801965164. Its totient is φ = 507600000.

The previous prime is 638138117. The next prime is 638138147. The reversal of 638138125 is 521831836.

It can be written as a sum of positive squares in 10 ways, for example, as 490976964 + 147161161 = 22158^2 + 12131^2 .

It is not a de Polignac number, because 638138125 - 2³ = 638138117 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 110305 + ... + 115945.

Almost surely, 2^638138125 is an apocalyptic number.

It is an amenable number.

638138125 is a deficient number, since it is larger than the sum of its proper divisors (163827039).

638138125 is an equidigital number, since it uses as much as digits as its factorization.

638138125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5842 (or 5827 counting only the distinct ones).

The product of its digits is 34560, while the sum is 37.

The square root of 638138125 is about 25261.3959432174. The cubic root of 638138125 is about 860.9373792961.

The spelling of 638138125 in words is "six hundred thirty-eight million, one hundred thirty-eight thousand, one hundred twenty-five".