18939 has 8 divisors (see below), whose sum is σ = 25920. Its totient is φ = 12296.

The previous prime is 18919. The next prime is 18947. The reversal of 18939 is 93981.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18939 - 2⁹ = 18427 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18919) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 124 + ... + 230.

It is an arithmetic number, because the mean of its divisors is an integer number (3240).

2¹⁸⁹³⁹ is an apocalyptic number.

18939 is a deficient number, since it is larger than the sum of its proper divisors (6981).

18939 is a wasteful number, since it uses less digits than its factorization.

18939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169.

The product of its digits is 1944, while the sum is 30.

The square root of 18939 is about 137.6190393805. The cubic root of 18939 is about 26.6554292930.

The spelling of 18939 in words is "eighteen thousand, nine hundred thirty-nine".