21122210 has 16 divisors (see below), whose sum is σ = 38390976. Its totient is φ = 8366448.

The previous prime is 21122203. The next prime is 21122221. The reversal of 21122210 is 1222112.

It is a happy number.

It is a super-2 number, since 2×21122210² = 892295510568200, which contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21122191 and 21122200.

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, 9224 + ... + 11283.

It is an arithmetic number, because the mean of its divisors is an integer number (2399436).

Almost surely, 2^21122210 is an apocalyptic number.

21122210 is a deficient number, since it is larger than the sum of its proper divisors (17268766).

21122210 is a wasteful number, since it uses less digits than its factorization.

21122210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20617.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 21122210 is about 4595.8905557030. The cubic root of 21122210 is about 276.4265703006.

Adding to 21122210 its reverse (1222112), we get a palindrome (22344322).

The spelling of 21122210 in words is "twenty-one million, one hundred twenty-two thousand, two hundred ten".