18739 has 4 divisors (see below), whose sum is σ = 21424. Its totient is φ = 16056.

The previous prime is 18731. The next prime is 18743. The reversal of 18739 is 93781.

18739 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93781 = 191 ⋅491.

It is a cyclic number.

It is not a de Polignac number, because 18739 - 2³ = 18731 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18731) 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 in 3 ways as a sum of consecutive naturals, for example, 1332 + ... + 1345.

It is an arithmetic number, because the mean of its divisors is an integer number (5356).

2¹⁸⁷³⁹ is an apocalyptic number.

18739 is a deficient number, since it is larger than the sum of its proper divisors (2685).

18739 is an equidigital number, since it uses as much as digits as its factorization.

18739 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2684.

The product of its digits is 1512, while the sum is 28.

The square root of 18739 is about 136.8904671626. The cubic root of 18739 is about 26.5612679936.

It can be divided in two parts, 18 and 739, that added together give a palindrome (757).

The spelling of 18739 in words is "eighteen thousand, seven hundred thirty-nine".