638108181081 has 12 divisors (see below), whose sum is σ = 1053384933952. Its totient is φ = 364633246296.

The previous prime is 638108181059. The next prime is 638108181167. The reversal of 638108181081 is 180181801836.

638108181081 is a `hidden beast` number, since 638 + 1 + 0 + 8 + 1 + 8 + 1 + 0 + 8 + 1 = 666.

It is not a de Polignac number, because 638108181081 - 2⁶ = 638108181017 is a prime.

It is a super-2 number, since 2×638108181081² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638108181031) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5064350581 + ... + 5064350706.

Almost surely, 2^638108181081 is an apocalyptic number.

It is an amenable number.

638108181081 is a deficient number, since it is larger than the sum of its proper divisors (415276752871).

638108181081 is a wasteful number, since it uses less digits than its factorization.

638108181081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10128701300 (or 10128701297 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 45.

The spelling of 638108181081 in words is "six hundred thirty-eight billion, one hundred eight million, one hundred eighty-one thousand, eighty-one".