21929772 has 48 divisors (see below), whose sum is σ = 53286912. Its totient is φ = 7011840.

The previous prime is 21929767. The next prime is 21929783. The reversal of 21929772 is 27792912.

It is a self number, because there is not a number n which added to its sum of digits gives 21929772.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 61948 + ... + 62300.

It is an arithmetic number, because the mean of its divisors is an integer number (1110144).

Almost surely, 2^21929772 is an apocalyptic number.

It is an amenable number.

21929772 is an abundant number, since it is smaller than the sum of its proper divisors (31357140).

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

21929772 is a wasteful number, since it uses less digits than its factorization.

21929772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 558 (or 556 counting only the distinct ones).

The product of its digits is 31752, while the sum is 39.

The square root of 21929772 is about 4682.9234458829. The cubic root of 21929772 is about 279.9054612810.

The spelling of 21929772 in words is "twenty-one million, nine hundred twenty-nine thousand, seven hundred seventy-two".