21339 has 6 divisors (see below), whose sum is σ = 30836. Its totient is φ = 14220.

The previous prime is 21323. The next prime is 21341. The reversal of 21339 is 93312.

It is not a de Polignac number, because 21339 - 2⁴ = 21323 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21319) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1177 + ... + 1194.

2²¹³³⁹ is an apocalyptic number.

21339 is a deficient number, since it is larger than the sum of its proper divisors (9497).

21339 is a wasteful number, since it uses less digits than its factorization.

21339 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2377 (or 2374 counting only the distinct ones).

The product of its digits is 162, while the sum is 18.

The square root of 21339 is about 146.0787458873. The cubic root of 21339 is about 27.7369064111.

Subtracting from 21339 its sum of digits (18), we obtain a triangular number (21321 = T₂₀₆).

It can be divided in two parts, 213 and 39, that added together give a palindrome (252).

The spelling of 21339 in words is "twenty-one thousand, three hundred thirty-nine".