21204210 has 32 divisors (see below), whose sum is σ = 51728832. Its totient is φ = 5561280.

The previous prime is 21204199. The next prime is 21204223. The reversal of 21204210 is 1240212.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3964 + ... + 7623.

It is an arithmetic number, because the mean of its divisors is an integer number (1616526).

Almost surely, 2^21204210 is an apocalyptic number.

21204210 is an abundant number, since it is smaller than the sum of its proper divisors (30524622).

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

21204210 is a wasteful number, since it uses less digits than its factorization.

21204210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11658.

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

The square root of 21204210 is about 4604.8029273792. The cubic root of 21204210 is about 276.7838199999.

Adding to 21204210 its reverse (1240212), we get a palindrome (22444422).

The spelling of 21204210 in words is "twenty-one million, two hundred four thousand, two hundred ten".