21668376 has 16 divisors (see below), whose sum is σ = 54171000. Its totient is φ = 7222784.

The previous prime is 21668327. The next prime is 21668389. The reversal of 21668376 is 67386612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 451401 + ... + 451448.

Almost surely, 2^21668376 is an apocalyptic number.

It is an amenable number.

21668376 is an abundant number, since it is smaller than the sum of its proper divisors (32502624).

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

21668376 is a wasteful number, since it uses less digits than its factorization.

21668376 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 902858 (or 902854 counting only the distinct ones).

The product of its digits is 72576, while the sum is 39.

The square root of 21668376 is about 4654.9302894888. The cubic root of 21668376 is about 278.7888846262.

The spelling of 21668376 in words is "twenty-one million, six hundred sixty-eight thousand, three hundred seventy-six".