21825972 has 54 divisors (see below), whose sum is σ = 64183938. Its totient is φ = 6235488.

The previous prime is 21825971. The next prime is 21825989. The reversal of 21825972 is 27952812.

It can be written as a sum of positive squares in only one way, i.e., 18714276 + 3111696 = 4326^2 + 1764^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21825971) 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 17 ways as a sum of consecutive naturals, for example, 4423 + ... + 7950.

Almost surely, 2^21825972 is an apocalyptic number.

It is an amenable number.

21825972 is an abundant number, since it is smaller than the sum of its proper divisors (42357966).

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

21825972 is a wasteful number, since it uses less digits than its factorization.

21825972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12397 (or 12385 counting only the distinct ones).

The product of its digits is 20160, while the sum is 36.

The square root of 21825972 is about 4671.8274796914. The cubic root of 21825972 is about 279.4631379644.

The spelling of 21825972 in words is "twenty-one million, eight hundred twenty-five thousand, nine hundred seventy-two".