21437952 has 80 divisors (see below), whose sum is σ = 60545232. Its totient is φ = 6717440.

The previous prime is 21437939. The next prime is 21437963. The reversal of 21437952 is 25973412.

It is a congruent number.

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, 25702 + ... + 26522.

Almost surely, 2^21437952 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 21437952, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30272616).

21437952 is an abundant number, since it is smaller than the sum of its proper divisors (39107280).

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

21437952 is an equidigital number, since it uses as much as digits as its factorization.

21437952 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 859 (or 843 counting only the distinct ones).

The product of its digits is 15120, while the sum is 33.

The square root of 21437952 is about 4630.1136055177. The cubic root of 21437952 is about 277.7971364760.

The spelling of 21437952 in words is "twenty-one million, four hundred thirty-seven thousand, nine hundred fifty-two".