638386513725 has 24 divisors (see below), whose sum is σ = 1055859425632. Its totient is φ = 340345800000.

The previous prime is 638386513691. The next prime is 638386513729. The reversal of 638386513725 is 527315683836.

It is a happy number.

638386513725 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 638386513725 - 2⁸ = 638386513469 is a prime.

It is a super-2 number, since 2×638386513725² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638386513729) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1385026 + ... + 1787475.

Almost surely, 2^638386513725 is an apocalyptic number.

It is an amenable number.

638386513725 is a deficient number, since it is larger than the sum of its proper divisors (417472911907).

638386513725 is a wasteful number, since it uses less digits than its factorization.

638386513725 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3175197 (or 3175192 counting only the distinct ones).

The product of its digits is 21772800, while the sum is 57.

The spelling of 638386513725 in words is "six hundred thirty-eight billion, three hundred eighty-six million, five hundred thirteen thousand, seven hundred twenty-five".