21237372 has 72 divisors (see below), whose sum is σ = 60357024. Its totient is φ = 6247296.

The previous prime is 21237353. The next prime is 21237389. The reversal of 21237372 is 27373212.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 9778 + ... + 11750.

It is an arithmetic number, because the mean of its divisors is an integer number (838292).

Almost surely, 2^21237372 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 21237372, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30178512).

21237372 is an abundant number, since it is smaller than the sum of its proper divisors (39119652).

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

21237372 is a wasteful number, since it uses less digits than its factorization.

21237372 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2019 (or 2014 counting only the distinct ones).

The product of its digits is 3528, while the sum is 27.

The square root of 21237372 is about 4608.4023261864. The cubic root of 21237372 is about 276.9280354525.

It can be divided in two parts, 21237 and 372, that added together give a square (21609 = 147²).

The spelling of 21237372 in words is "twenty-one million, two hundred thirty-seven thousand, three hundred seventy-two".