21573232 has 20 divisors (see below), whose sum is σ = 42508440. Its totient is φ = 10603328.

The previous prime is 21573203. The next prime is 21573239. The reversal of 21573232 is 23237512.

It is a junction number, because it is equal to n+sod(n) for n = 21573197 and 21573206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21573239) 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 3 ways as a sum of consecutive naturals, for example, 10483 + ... + 12370.

It is an arithmetic number, because the mean of its divisors is an integer number (2125422).

Almost surely, 2^21573232 is an apocalyptic number.

It is an amenable number.

21573232 is a deficient number, since it is larger than the sum of its proper divisors (20935208).

21573232 is a wasteful number, since it uses less digits than its factorization.

21573232 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22920 (or 22914 counting only the distinct ones).

The product of its digits is 2520, while the sum is 25.

The square root of 21573232 is about 4644.6993444140. The cubic root of 21573232 is about 278.3802398227.

The spelling of 21573232 in words is "twenty-one million, five hundred seventy-three thousand, two hundred thirty-two".