21667684 has 12 divisors (see below), whose sum is σ = 37972144. Its totient is φ = 10818504.

The previous prime is 21667651. The next prime is 21667703. The reversal of 21667684 is 48676612.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 294 + ... + 6589.

Almost surely, 2^21667684 is an apocalyptic number.

It is an amenable number.

21667684 is a deficient number, since it is larger than the sum of its proper divisors (16304460).

21667684 is a wasteful number, since it uses less digits than its factorization.

21667684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7674 (or 7672 counting only the distinct ones).

The product of its digits is 96768, while the sum is 40.

The square root of 21667684 is about 4654.8559591034. The cubic root of 21667684 is about 278.7859167994.

The spelling of 21667684 in words is "twenty-one million, six hundred sixty-seven thousand, six hundred eighty-four".