21668364 has 48 divisors (see below), whose sum is σ = 56444640. Its totient is φ = 7188480.

The previous prime is 21668327. The next prime is 21668389. The reversal of 21668364 is 46386612.

It is a Harshad number since it is a multiple of its sum of digits (36).

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, 33484 + ... + 34124.

It is an arithmetic number, because the mean of its divisors is an integer number (1175930).

Almost surely, 2^21668364 is an apocalyptic number.

It is an amenable number.

21668364 is an abundant number, since it is smaller than the sum of its proper divisors (34776276).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21668364 is a wasteful number, since it uses less digits than its factorization.

21668364 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 967 (or 959 counting only the distinct ones).

The product of its digits is 41472, while the sum is 36.

The square root of 21668364 is about 4654.9290005327. The cubic root of 21668364 is about 278.7888331616.

The spelling of 21668364 in words is "twenty-one million, six hundred sixty-eight thousand, three hundred sixty-four".