21112121222111 has 4 divisors (see below), whose sum is σ = 21253813311000. Its totient is φ = 20970429133224.

The previous prime is 21112121222063. The next prime is 21112121222147. The reversal of 21112121222111 is 11122212121112.

It is a happy number.

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 21112121222111 - 2⁶ = 21112121222047 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 (21112121422111) 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, 70846044221 + ... + 70846044518.

It is an arithmetic number, because the mean of its divisors is an integer number (5313453327750).

Almost surely, 2^{21112121222111} is an apocalyptic number.

21112121222111 is a deficient number, since it is larger than the sum of its proper divisors (141692088889).

21112121222111 is a wasteful number, since it uses less digits than its factorization.

21112121222111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141692088888.

The product of its digits is 64, while the sum is 20.

Adding to 21112121222111 its reverse (11122212121112), we get a palindrome (32234333343223).

The spelling of 21112121222111 in words is "twenty-one trillion, one hundred twelve billion, one hundred twenty-one million, two hundred twenty-two thousand, one hundred eleven".