18639169 has 2 divisors, whose sum is σ = 18639170. Its totient is φ = 18639168.

The previous prime is 18639161. The next prime is 18639217. The reversal of 18639169 is 96193681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17850625 + 788544 = 4225^2 + 888^2 .

It is a cyclic number.

It is not a de Polignac number, because 18639169 - 2³ = 18639161 is a prime.

It is a super-2 number, since 2×18639169² = 694837242021122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18639161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9319584 + 9319585.

It is an arithmetic number, because the mean of its divisors is an integer number (9319585).

Almost surely, 2^18639169 is an apocalyptic number.

It is an amenable number.

18639169 is a deficient number, since it is larger than the sum of its proper divisors (1).

18639169 is an equidigital number, since it uses as much as digits as its factorization.

18639169 is an evil number, because the sum of its binary digits is even.

The product of its digits is 69984, while the sum is 43.

The square root of 18639169 is about 4317.3103895828. The cubic root of 18639169 is about 265.1401608137.

The spelling of 18639169 in words is "eighteen million, six hundred thirty-nine thousand, one hundred sixty-nine".