21947232 has 24 divisors (see below), whose sum is σ = 57611736. Its totient is φ = 7315712.

The previous prime is 21947213. The next prime is 21947249. The reversal of 21947232 is 23274912.

It is a tau number, because it is divible by the number of its divisors (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21947232.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 114213 + ... + 114404.

It is an arithmetic number, because the mean of its divisors is an integer number (2400489).

Almost surely, 2^21947232 is an apocalyptic number.

It is an amenable number.

21947232 is an abundant number, since it is smaller than the sum of its proper divisors (35664504).

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

21947232 is a wasteful number, since it uses less digits than its factorization.

21947232 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 228630 (or 228622 counting only the distinct ones).

The product of its digits is 6048, while the sum is 30.

The square root of 21947232 is about 4684.7872950647. The cubic root of 21947232 is about 279.9797264233.

The spelling of 21947232 in words is "twenty-one million, nine hundred forty-seven thousand, two hundred thirty-two".