21563232 has 24 divisors (see below), whose sum is σ = 56603736. Its totient is φ = 7187712.

The previous prime is 21563219. The next prime is 21563237. The reversal of 21563232 is 23236512.

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

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21563237) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 112213 + ... + 112404.

It is an arithmetic number, because the mean of its divisors is an integer number (2358489).

Almost surely, 2^21563232 is an apocalyptic number.

It is an amenable number.

21563232 is an abundant number, since it is smaller than the sum of its proper divisors (35040504).

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

21563232 is a wasteful number, since it uses less digits than its factorization.

21563232 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 224630 (or 224622 counting only the distinct ones).

The product of its digits is 2160, while the sum is 24.

The square root of 21563232 is about 4643.6227236932. The cubic root of 21563232 is about 278.3372199568.

Adding to 21563232 its reverse (23236512), we get a palindrome (44799744).

The spelling of 21563232 in words is "twenty-one million, five hundred sixty-three thousand, two hundred thirty-two".