21221111111211 has 32 divisors (see below), whose sum is σ = 34304811402240. Its totient is φ = 12858254647200.

The previous prime is 21221111111177. The next prime is 21221111111231. The reversal of 21221111111211 is 11211111112212.

21221111111211 is a `hidden beast` number, since 212 + 21 + 111 + 111 + 211 = 666.

It is not a de Polignac number, because 21221111111211 - 2⁶ = 21221111111147 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21221111111231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7136995 + ... + 9663276.

It is an arithmetic number, because the mean of its divisors is an integer number (1072025356320).

Almost surely, 2^{21221111111211} is an apocalyptic number.

21221111111211 is a deficient number, since it is larger than the sum of its proper divisors (13083700291029).

21221111111211 is a wasteful number, since it uses less digits than its factorization.

21221111111211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16804544 (or 16804538 counting only the distinct ones).

The product of its digits is 16, while the sum is 18.

Adding to 21221111111211 its reverse (11211111112212), we get a palindrome (32432222223423).

The spelling of 21221111111211 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred eleven million, one hundred eleven thousand, two hundred eleven".