21660772 has 12 divisors (see below), whose sum is σ = 43321600. Its totient is φ = 9283176.

The previous prime is 21660761. The next prime is 21660791. The reversal of 21660772 is 27706612.

21660772 is an admirable 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, 386772 + ... + 386827.

Almost surely, 2^21660772 is an apocalyptic number.

It is an amenable number.

21660772 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21660772 is a wasteful number, since it uses less digits than its factorization.

21660772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 773610 (or 773608 counting only the distinct ones).

The product of its (nonzero) digits is 7056, while the sum is 31.

The square root of 21660772 is about 4654.1134494123. The cubic root of 21660772 is about 278.7562693731.

The spelling of 21660772 in words is "twenty-one million, six hundred sixty thousand, seven hundred seventy-two".