221111212112121 has 16 divisors (see below), whose sum is σ = 302783366906624. Its totient is φ = 143423277761664.

The previous prime is 221111212112107. The next prime is 221111212112137. The reversal of 221111212112121 is 121211212111122.

It is not a de Polignac number, because 221111212112121 - 2¹¹ = 221111212110073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221111212112191) 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, 117639696 + ... + 119504478.

It is an arithmetic number, because the mean of its divisors is an integer number (18923960431664).

Almost surely, 2^{221111212112121} is an apocalyptic number.

It is an amenable number.

221111212112121 is a deficient number, since it is larger than the sum of its proper divisors (81672154794503).

221111212112121 is a wasteful number, since it uses less digits than its factorization.

221111212112121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2933040.

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

Adding to 221111212112121 its reverse (121211212111122), we get a palindrome (342322424223243).

Subtracting from 221111212112121 its reverse (121211212111122), we obtain a palindrome (99900000000999).

The spelling of 221111212112121 in words is "two hundred twenty-one trillion, one hundred eleven billion, two hundred twelve million, one hundred twelve thousand, one hundred twenty-one".