211221111111111 has 24 divisors (see below), whose sum is σ = 310126780922400. Its totient is φ = 138511061499456.

The previous prime is 211221111111097. The next prime is 211221111111169. The reversal of 211221111111111 is 111111111122112.

211221111111111 is a `hidden beast` number, since 211 + 221 + 1 + 11 + 111 + 111 = 666.

It is not a de Polignac number, because 211221111111111 - 2²⁶ = 211221044002247 is a prime.

It is a super-2 number, since 2×211221111111111² (a number of 29 digits) contains 22 as substring.

211221111111111 is a modest number, since divided by 11111111 gives 2112211 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211221111111811) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 764474256 + ... + 764750501.

It is an arithmetic number, because the mean of its divisors is an integer number (12921949205100).

Almost surely, 2^{211221111111111} is an apocalyptic number.

211221111111111 is a deficient number, since it is larger than the sum of its proper divisors (98905669811289).

211221111111111 is a wasteful number, since it uses less digits than its factorization.

211221111111111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1529225015 (or 1529225012 counting only the distinct ones).

The product of its digits is 8, while the sum is 18.

Adding to 211221111111111 its reverse (111111111122112), we get a palindrome (322332222233223).

It can be divided in two parts, 21122111 and 1111111, that added together give a palindrome (22233222).

The spelling of 211221111111111 in words is "two hundred eleven trillion, two hundred twenty-one billion, one hundred eleven million, one hundred eleven thousand, one hundred eleven".