21682839 has 16 divisors (see below), whose sum is σ = 29832192. Its totient is φ = 14000928.

The previous prime is 21682823. The next prime is 21682847. The reversal of 21682839 is 93828612.

It is a happy number.

It is not a de Polignac number, because 21682839 - 2⁴ = 21682823 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21682797 and 21682806.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21682849) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13777 + ... + 15269.

It is an arithmetic number, because the mean of its divisors is an integer number (1864512).

Almost surely, 2^21682839 is an apocalyptic number.

21682839 is a deficient number, since it is larger than the sum of its proper divisors (8149353).

21682839 is a wasteful number, since it uses less digits than its factorization.

21682839 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1646.

The product of its digits is 41472, while the sum is 39.

The square root of 21682839 is about 4656.4835444786. The cubic root of 21682839 is about 278.8508986086.

The spelling of 21682839 in words is "twenty-one million, six hundred eighty-two thousand, eight hundred thirty-nine".