21112111212111 has 16 divisors (see below), whose sum is σ = 31401812171520. Its totient is φ = 14018666139000.

The previous prime is 21112111212091. The next prime is 21112111212139. The reversal of 21112111212111 is 11121211121112.

21112111212111 is a `hidden beast` number, since 211 + 121 + 1 + 121 + 211 + 1 = 666.

It is not a de Polignac number, because 21112111212111 - 2⁹ = 21112111211599 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112111212011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1557622795 + ... + 1557636348.

It is an arithmetic number, because the mean of its divisors is an integer number (1962613260720).

Almost surely, 2^{21112111212111} is an apocalyptic number.

21112111212111 is a deficient number, since it is larger than the sum of its proper divisors (10289700959409).

21112111212111 is a wasteful number, since it uses less digits than its factorization.

21112111212111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3115259403 (or 3115259397 counting only the distinct ones).

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

Adding to 21112111212111 its reverse (11121211121112), we get a palindrome (32233322333223).

Subtracting from 21112111212111 its reverse (11121211121112), we obtain a palindrome (9990900090999).

The spelling of 21112111212111 in words is "twenty-one trillion, one hundred twelve billion, one hundred eleven million, two hundred twelve thousand, one hundred eleven".