21576972 has 12 divisors (see below), whose sum is σ = 50346296. Its totient is φ = 7192320.

The previous prime is 21576959. The next prime is 21576979. The reversal of 21576972 is 27967512.

It is a tau number, because it is divible by the number of its divisors (12).

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

It is a self number, because there is not a number n which added to its sum of digits gives 21576972.

It is not an unprimeable number, because it can be changed into a prime (21576979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 899029 + ... + 899052.

Almost surely, 2^21576972 is an apocalyptic number.

It is an amenable number.

21576972 is an abundant number, since it is smaller than the sum of its proper divisors (28769324).

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

21576972 is a wasteful number, since it uses less digits than its factorization.

21576972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1798088 (or 1798086 counting only the distinct ones).

The product of its digits is 52920, while the sum is 39.

The square root of 21576972 is about 4645.1019364488. The cubic root of 21576972 is about 278.3963258367.

The spelling of 21576972 in words is "twenty-one million, five hundred seventy-six thousand, nine hundred seventy-two".