18688139 has 2 divisors, whose sum is σ = 18688140. Its totient is φ = 18688138.

The previous prime is 18688091. The next prime is 18688157. The reversal of 18688139 is 93188681.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18688139 - 2⁸ = 18687883 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18688139.

It is not a weakly prime, because it can be changed into another prime (18688639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9344069 + 9344070.

It is an arithmetic number, because the mean of its divisors is an integer number (9344070).

Almost surely, 2^18688139 is an apocalyptic number.

18688139 is a deficient number, since it is larger than the sum of its proper divisors (1).

18688139 is an equidigital number, since it uses as much as digits as its factorization.

18688139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 82944, while the sum is 44.

The square root of 18688139 is about 4322.9780244642. The cubic root of 18688139 is about 265.3721554111.

The spelling of 18688139 in words is "eighteen million, six hundred eighty-eight thousand, one hundred thirty-nine".