21906339 has 32 divisors (see below), whose sum is σ = 37201920. Its totient is φ = 11152512.

The previous prime is 21906337. The next prime is 21906359. The reversal of 21906339 is 93360912.

It is not a de Polignac number, because 21906339 - 2¹ = 21906337 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21906337) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6534 + ... + 9300.

It is an arithmetic number, because the mean of its divisors is an integer number (1162560).

Almost surely, 2^21906339 is an apocalyptic number.

21906339 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

21906339 is a deficient number, since it is larger than the sum of its proper divisors (15295581).

21906339 is a wasteful number, since it uses less digits than its factorization.

21906339 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2819.

The product of its (nonzero) digits is 8748, while the sum is 33.

The square root of 21906339 is about 4680.4208144140. The cubic root of 21906339 is about 279.8057283354.

The spelling of 21906339 in words is "twenty-one million, nine hundred six thousand, three hundred thirty-nine".