18539 has 2 divisors, whose sum is σ = 18540. Its totient is φ = 18538.

The previous prime is 18523. The next prime is 18541. The reversal of 18539 is 93581.

It is a strong prime.

It is an emirp because it is prime and its reverse (93581) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18539 - 2⁴ = 18523 is a prime.

Together with 18541, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18439) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9269 + 9270.

It is an arithmetic number, because the mean of its divisors is an integer number (9270).

2¹⁸⁵³⁹ is an apocalyptic number.

18539 is a deficient number, since it is larger than the sum of its proper divisors (1).

18539 is an equidigital number, since it uses as much as digits as its factorization.

18539 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1080, while the sum is 26.

The square root of 18539 is about 136.1579964600. The cubic root of 18539 is about 26.4664343034.

The spelling of 18539 in words is "eighteen thousand, five hundred thirty-nine".