21012204 has 24 divisors (see below), whose sum is σ = 51913008. Its totient is φ = 6592000.

The previous prime is 21012193. The next prime is 21012227. The reversal of 21012204 is 40221012.

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 21012204.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51297 + ... + 51704.

It is an arithmetic number, because the mean of its divisors is an integer number (2163042).

Almost surely, 2^21012204 is an apocalyptic number.

It is an amenable number.

21012204 is an abundant number, since it is smaller than the sum of its proper divisors (30900804).

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

21012204 is a wasteful number, since it uses less digits than its factorization.

21012204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103025 (or 103023 counting only the distinct ones).

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

The square root of 21012204 is about 4583.9070671208. The cubic root of 21012204 is about 275.9458515911.

Adding to 21012204 its reverse (40221012), we get a palindrome (61233216).

The spelling of 21012204 in words is "twenty-one million, twelve thousand, two hundred four".