18442139 has 2 divisors, whose sum is σ = 18442140. Its totient is φ = 18442138.

The previous prime is 18442129. The next prime is 18442147. The reversal of 18442139 is 93124481.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18442139 is a prime.

It is a super-2 number, since 2×18442139² = 680224981790642, which contains 22 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (18442129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9221069 + 9221070.

It is an arithmetic number, because the mean of its divisors is an integer number (9221070).

Almost surely, 2^18442139 is an apocalyptic number.

18442139 is a deficient number, since it is larger than the sum of its proper divisors (1).

18442139 is an equidigital number, since it uses as much as digits as its factorization.

18442139 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6912, while the sum is 32.

The square root of 18442139 is about 4294.4311613996. The cubic root of 18442139 is about 264.2026059876.

It can be divided in two parts, 18442 and 139, that added together give a palindrome (18581).

The spelling of 18442139 in words is "eighteen million, four hundred forty-two thousand, one hundred thirty-nine".