21339605 has 16 divisors (see below), whose sum is σ = 29366400. Its totient is φ = 14582592.

The previous prime is 21339599. The next prime is 21339629. The reversal of 21339605 is 50693312.

It is a cyclic number.

It is not a de Polignac number, because 21339605 - 2⁸ = 21339349 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11342 + ... + 13088.

It is an arithmetic number, because the mean of its divisors is an integer number (1835400).

Almost surely, 2^21339605 is an apocalyptic number.

It is an amenable number.

21339605 is a deficient number, since it is larger than the sum of its proper divisors (8026795).

21339605 is a wasteful number, since it uses less digits than its factorization.

21339605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2108.

The product of its (nonzero) digits is 4860, while the sum is 29.

The square root of 21339605 is about 4619.4810314580. The cubic root of 21339605 is about 277.3716853948.

The spelling of 21339605 in words is "twenty-one million, three hundred thirty-nine thousand, six hundred five".