638620638923169 has 48 divisors (see below), whose sum is σ = 1116368370748800. Its totient is φ = 343421718612480.

The previous prime is 638620638923161. The next prime is 638620638923257. The reversal of 638620638923169 is 961329836026836.

638620638923169 is a `hidden beast` number, since 6 + 3 + 8 + 6 + 2 + 0 + 6 + 389 + 231 + 6 + 9 = 666.

It is not a de Polignac number, because 638620638923169 - 2³ = 638620638923161 is a prime.

It is a super-2 number, since 2×638620638923169² (a number of 30 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 638620638923097 and 638620638923106.

It is not an unprimeable number, because it can be changed into a prime (638620638923161) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 23435694 + ... + 42737255.

It is an arithmetic number, because the mean of its divisors is an integer number (23257674390600).

Almost surely, 2^{638620638923169} is an apocalyptic number.

It is an amenable number.

638620638923169 is a deficient number, since it is larger than the sum of its proper divisors (477747731825631).

638620638923169 is a wasteful number, since it uses less digits than its factorization.

638620638923169 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66181990 (or 66181987 counting only the distinct ones).

The product of its (nonzero) digits is 725594112, while the sum is 72.

The spelling of 638620638923169 in words is "six hundred thirty-eight trillion, six hundred twenty billion, six hundred thirty-eight million, nine hundred twenty-three thousand, one hundred sixty-nine".