221111102121 has 128 divisors (see below), whose sum is σ = 377775906816. Its totient is φ = 111929610240.

The previous prime is 221111102083. The next prime is 221111102129. The reversal of 221111102121 is 121201111122.

It is a happy number.

It is not a de Polignac number, because 221111102121 - 2⁹ = 221111101609 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 221111102121.

It is not an unprimeable number, because it can be changed into a prime (221111102129) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 350413476 + ... + 350414106.

It is an arithmetic number, because the mean of its divisors is an integer number (2951374272).

Almost surely, 2^221111102121 is an apocalyptic number.

221111102121 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

221111102121 is a deficient number, since it is larger than the sum of its proper divisors (156664804695).

221111102121 is a wasteful number, since it uses less digits than its factorization.

221111102121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1111.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 221111102121 its reverse (121201111122), we get a palindrome (342312213243).

Subtracting from 221111102121 its reverse (121201111122), we obtain a palindrome (99909990999).

The spelling of 221111102121 in words is "two hundred twenty-one billion, one hundred eleven million, one hundred two thousand, one hundred twenty-one".