21221211112111 has 4 divisors (see below), whose sum is σ = 21221348993824. Its totient is φ = 21221073230400.

The previous prime is 21221211112097. The next prime is 21221211112181. The reversal of 21221211112111 is 11121111212212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21221211112111 - 2⁹ = 21221211111599 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221211112181) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68709735 + ... + 69017896.

It is an arithmetic number, because the mean of its divisors is an integer number (5305337248456).

Almost surely, 2^{21221211112111} is an apocalyptic number.

21221211112111 is a deficient number, since it is larger than the sum of its proper divisors (137881713).

21221211112111 is a wasteful number, since it uses less digits than its factorization.

21221211112111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137881712.

The product of its digits is 32, while the sum is 19.

Adding to 21221211112111 its reverse (11121111212212), we get a palindrome (32342322324323).

The spelling of 21221211112111 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred eleven million, one hundred twelve thousand, one hundred eleven".