21102204 has 24 divisors (see below), whose sum is σ = 49367248. Its totient is φ = 7015680.

The previous prime is 21102199. The next prime is 21102209. The reversal of 21102204 is 40220112.

It is an interprime number because it is at equal distance from previous prime (21102199) and next prime (21102209).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a self number, because there is not a number n which added to its sum of digits gives 21102204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21102209) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2964 + ... + 7140.

Almost surely, 2^21102204 is an apocalyptic number.

It is an amenable number.

21102204 is an abundant number, since it is smaller than the sum of its proper divisors (28265044).

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

21102204 is a wasteful number, since it uses less digits than its factorization.

21102204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4605 (or 4603 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

The square root of 21102204 is about 4593.7135304675. The cubic root of 21102204 is about 276.3392698261.

Adding to 21102204 its reverse (40220112), we get a palindrome (61322316).

The spelling of 21102204 in words is "twenty-one million, one hundred two thousand, two hundred four".