21722908 has 6 divisors (see below), whose sum is σ = 38015096. Its totient is φ = 10861452.

The previous prime is 21722891. The next prime is 21722929. The reversal of 21722908 is 80922712.

It is a self number, because there is not a number n which added to its sum of digits gives 21722908.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2715360 + ... + 2715367.

Almost surely, 2^21722908 is an apocalyptic number.

It is an amenable number.

21722908 is a deficient number, since it is larger than the sum of its proper divisors (16292188).

21722908 is a wasteful number, since it uses less digits than its factorization.

21722908 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5430731 (or 5430729 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 21722908 is about 4660.7840542123. The cubic root of 21722908 is about 279.0225612635.

The spelling of 21722908 in words is "twenty-one million, seven hundred twenty-two thousand, nine hundred eight".