21673868 has 12 divisors (see below), whose sum is σ = 38072160. Its totient is φ = 10796112.

The previous prime is 21673859. The next prime is 21673921. The reversal of 21673868 is 86837612.

It is a happy number.

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, 8996 + ... + 11147.

It is an arithmetic number, because the mean of its divisors is an integer number (3172680).

Almost surely, 2^21673868 is an apocalyptic number.

It is an amenable number.

21673868 is a deficient number, since it is larger than the sum of its proper divisors (16398292).

21673868 is a wasteful number, since it uses less digits than its factorization.

21673868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20416 (or 20414 counting only the distinct ones).

The product of its digits is 96768, while the sum is 41.

The square root of 21673868 is about 4655.5201642781. The cubic root of 21673868 is about 278.8124362946.

The spelling of 21673868 in words is "twenty-one million, six hundred seventy-three thousand, eight hundred sixty-eight".