18638131 has 2 divisors, whose sum is σ = 18638132. Its totient is φ = 18638130.

The previous prime is 18638111. The next prime is 18638177. The reversal of 18638131 is 13183681.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18638131 - 2⁷ = 18638003 is a prime.

It is a super-2 number, since 2×18638131² = 694759854346322, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 18638093 and 18638102.

It is not a weakly prime, because it can be changed into another prime (18638101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9319065 + 9319066.

It is an arithmetic number, because the mean of its divisors is an integer number (9319066).

Almost surely, 2^18638131 is an apocalyptic number.

18638131 is a deficient number, since it is larger than the sum of its proper divisors (1).

18638131 is an equidigital number, since it uses as much as digits as its factorization.

18638131 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3456, while the sum is 31.

The square root of 18638131 is about 4317.1901741758. The cubic root of 18638131 is about 265.1352389098.

It can be divided in two parts, 18638 and 131, that added together give a square (18769 = 137²).

The spelling of 18638131 in words is "eighteen million, six hundred thirty-eight thousand, one hundred thirty-one".