18831139 has 2 divisors, whose sum is σ = 18831140. Its totient is φ = 18831138.

The previous prime is 18831107. The next prime is 18831191. The reversal of 18831139 is 93113881.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18831139 - 2⁵ = 18831107 is a prime.

It is a super-2 number, since 2×18831139² = 709223592074642, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18831199) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9415569 + 9415570.

It is an arithmetic number, because the mean of its divisors is an integer number (9415570).

Almost surely, 2^18831139 is an apocalyptic number.

18831139 is a deficient number, since it is larger than the sum of its proper divisors (1).

18831139 is an equidigital number, since it uses as much as digits as its factorization.

18831139 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5184, while the sum is 34.

The square root of 18831139 is about 4339.4860294740. The cubic root of 18831139 is about 266.0473044180.

The spelling of 18831139 in words is "eighteen million, eight hundred thirty-one thousand, one hundred thirty-nine".