21122211 has 32 divisors (see below), whose sum is σ = 33965568. Its totient is φ = 11517440.

The previous prime is 21122203. The next prime is 21122221. The reversal of 21122211 is 11222112.

It is not a de Polignac number, because 21122211 - 2³ = 21122203 is a prime.

It is a super-2 number, since 2×21122211² = 892295595057042, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21122201) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12085 + ... + 13721.

It is an arithmetic number, because the mean of its divisors is an integer number (1061424).

Almost surely, 2^21122211 is an apocalyptic number.

21122211 is a deficient number, since it is larger than the sum of its proper divisors (12843357).

21122211 is a wasteful number, since it uses less digits than its factorization.

21122211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1691.

The product of its digits is 16, while the sum is 12.

The square root of 21122211 is about 4595.8906644958. The cubic root of 21122211 is about 276.4265746630.

Adding to 21122211 its reverse (11222112), we get a palindrome (32344323).

Subtracting from 21122211 its reverse (11222112), we obtain a palindrome (9900099).

It can be divided in two parts, 211 and 22211, that added together give a palindrome (22422).

The spelling of 21122211 in words is "twenty-one million, one hundred twenty-two thousand, two hundred eleven".