21115210 has 16 divisors (see below), whose sum is σ = 38069856. Its totient is φ = 8432208.

The previous prime is 21115189. The next prime is 21115229. The reversal of 21115210 is 1251112.

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, 6529 + ... + 9211.

It is an arithmetic number, because the mean of its divisors is an integer number (2379366).

Almost surely, 2^21115210 is an apocalyptic number.

21115210 is a deficient number, since it is larger than the sum of its proper divisors (16954646).

21115210 is a wasteful number, since it uses less digits than its factorization.

21115210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3477.

The product of its (nonzero) digits is 20, while the sum is 13.

The square root of 21115210 is about 4595.1289426957. The cubic root of 21115210 is about 276.3960305704.

Adding to 21115210 its reverse (1251112), we get a palindrome (22366322).

The spelling of 21115210 in words is "twenty-one million, one hundred fifteen thousand, two hundred ten".