636317138 has 6 divisors (see below), whose sum is σ = 954529221. Its totient is φ = 318140732.

The previous prime is 636317137. The next prime is 636317177. The reversal of 636317138 is 831713636.

It can be written as a sum of positive squares in 2 ways, for example, as 542750209 + 93566929 = 23297^2 + 9673^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=17837.

It is a super-2 number, since 2×636317138² = 809799000225022088, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (636317137) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 26756 + ... + 44592.

Almost surely, 2^636317138 is an apocalyptic number.

636317138 is a deficient number, since it is larger than the sum of its proper divisors (318212083).

636317138 is an frugal number, since it uses more digits than its factorization.

636317138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35676 (or 17839 counting only the distinct ones).

The product of its digits is 54432, while the sum is 38.

The square root of 636317138 is about 25225.3273120489. The cubic root of 636317138 is about 860.1176772448.

The spelling of 636317138 in words is "six hundred thirty-six million, three hundred seventeen thousand, one hundred thirty-eight".