21210204 has 12 divisors (see below), whose sum is σ = 49490504. Its totient is φ = 7070064.

The previous prime is 21210197. The next prime is 21210221. The reversal of 21210204 is 40201212.

It is a tau number, because it is divible by the number of its divisors (12).

It is a Harshad number since it is a multiple of its sum of digits (12), and also a Moran number because the ratio is a prime number: 1767517 = 21210204 / (2 + 1 + 2 + 1 + 0 + 2 + 0 + 4).

It is a self number, because there is not a number n which added to its sum of digits gives 21210204.

It is a congruent number.

It is an unprimeable number.

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, 883747 + ... + 883770.

Almost surely, 2^21210204 is an apocalyptic number.

It is an amenable number.

21210204 is an abundant number, since it is smaller than the sum of its proper divisors (28280300).

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

21210204 is a wasteful number, since it uses less digits than its factorization.

21210204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1767524 (or 1767522 counting only the distinct ones).

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

The square root of 21210204 is about 4605.4537235760. The cubic root of 21210204 is about 276.8098979331.

Adding to 21210204 its reverse (40201212), we get a palindrome (61411416).

The spelling of 21210204 in words is "twenty-one million, two hundred ten thousand, two hundred four".