111111122222121 has 16 divisors (see below), whose sum is σ = 169325870643584. Its totient is φ = 63486938191104.

The previous prime is 111111122222033. The next prime is 111111122222183. The reversal of 111111122222121 is 121222221111111.

It is not a de Polignac number, because 111111122222121 - 2²⁶ = 111111055113257 is a prime.

It is a super-2 number, since 2×111111122222121² (a number of 29 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (111111122202121) 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, 213552736 + ... + 214072401.

It is an arithmetic number, because the mean of its divisors is an integer number (10582866915224).

Almost surely, 2^{111111122222121} is an apocalyptic number.

It is an amenable number.

111111122222121 is a deficient number, since it is larger than the sum of its proper divisors (58214748421463).

111111122222121 is a wasteful number, since it uses less digits than its factorization.

111111122222121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 427637520.

The product of its digits is 64, while the sum is 21.

Adding to 111111122222121 its reverse (121222221111111), we get a palindrome (232333343333232).

The spelling of 111111122222121 in words is "one hundred eleven trillion, one hundred eleven billion, one hundred twenty-two million, two hundred twenty-two thousand, one hundred twenty-one".