21979272 has 32 divisors (see below), whose sum is σ = 62798400. Its totient is φ = 6279744.

The previous prime is 21979267. The next prime is 21979289. The reversal of 21979272 is 27297912.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 21979272.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 65247 + ... + 65582.

It is an arithmetic number, because the mean of its divisors is an integer number (1962450).

Almost surely, 2^21979272 is an apocalyptic number.

It is an amenable number.

21979272 is an abundant number, since it is smaller than the sum of its proper divisors (40819128).

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

21979272 is a wasteful number, since it uses less digits than its factorization.

21979272 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130845 (or 130841 counting only the distinct ones).

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

The square root of 21979272 is about 4688.2056268897. The cubic root of 21979272 is about 280.1159043964.

The spelling of 21979272 in words is "twenty-one million, nine hundred seventy-nine thousand, two hundred seventy-two".