21213232 has 20 divisors (see below), whose sum is σ = 41510736. Its totient is φ = 10500800.

The previous prime is 21213193. The next prime is 21213251. The reversal of 21213232 is 23231212.

It is a Harshad number since it is a multiple of its sum of digits (16).

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, 4948 + ... + 8179.

Almost surely, 2^21213232 is an apocalyptic number.

It is an amenable number.

21213232 is a deficient number, since it is larger than the sum of its proper divisors (20297504).

21213232 is a wasteful number, since it uses less digits than its factorization.

21213232 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13236 (or 13230 counting only the distinct ones).

The product of its digits is 144, while the sum is 16.

The square root of 21213232 is about 4605.7824525264. The cubic root of 21213232 is about 276.8230699027.

Adding to 21213232 its reverse (23231212), we get a palindrome (44444444).

The spelling of 21213232 in words is "twenty-one million, two hundred thirteen thousand, two hundred thirty-two".