21972552 has 64 divisors (see below), whose sum is σ = 64819200. Its totient is φ = 6073920.

The previous prime is 21972539. The next prime is 21972553. The reversal of 21972552 is 25527912.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21972553) 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 15 ways as a sum of consecutive naturals, for example, 3099 + ... + 7317.

It is an arithmetic number, because the mean of its divisors is an integer number (1012800).

Almost surely, 2^21972552 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21972552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32409600).

21972552 is an abundant number, since it is smaller than the sum of its proper divisors (42846648).

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

21972552 is a wasteful number, since it uses less digits than its factorization.

21972552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4266 (or 4262 counting only the distinct ones).

The product of its digits is 12600, while the sum is 33.

The square root of 21972552 is about 4687.4888799868. The cubic root of 21972552 is about 280.0873536972.

It can be divided in two parts, 219 and 72552, that added together give a triangular number (72771 = T₃₈₁).

The spelling of 21972552 in words is "twenty-one million, nine hundred seventy-two thousand, five hundred fifty-two".