21684976 has 10 divisors (see below), whose sum is σ = 42014672. Its totient is φ = 10842480.

The previous prime is 21684967. The next prime is 21684977. The reversal of 21684976 is 67948612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21684977) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 677640 + ... + 677671.

Almost surely, 2^21684976 is an apocalyptic number.

It is an amenable number.

21684976 is a deficient number, since it is larger than the sum of its proper divisors (20329696).

21684976 is a wasteful number, since it uses less digits than its factorization.

21684976 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1355319 (or 1355313 counting only the distinct ones).

The product of its digits is 145152, while the sum is 43.

The square root of 21684976 is about 4656.7130038258. The cubic root of 21684976 is about 278.8600592294.

The spelling of 21684976 in words is "twenty-one million, six hundred eighty-four thousand, nine hundred seventy-six".