221220022121 has 24 divisors (see below), whose sum is σ = 271282553280. Its totient is φ = 179371456992.

The previous prime is 221220022099. The next prime is 221220022141. The reversal of 221220022121 is 121220022122.

It is a happy number.

It is not a de Polignac number, because 221220022121 - 2¹⁸ = 221219759977 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 221220022121.

It is not an unprimeable number, because it can be changed into a prime (221220022141) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 454796 + ... + 805778.

It is an arithmetic number, because the mean of its divisors is an integer number (11303439720).

Almost surely, 2^221220022121 is an apocalyptic number.

It is an amenable number.

221220022121 is a deficient number, since it is larger than the sum of its proper divisors (50062531159).

221220022121 is a wasteful number, since it uses less digits than its factorization.

221220022121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 351693 (or 351686 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 221220022121 its reverse (121220022122), we get a palindrome (342440044243).

Subtracting from 221220022121 its reverse (121220022122), we obtain a palindrome (99999999999).

The spelling of 221220022121 in words is "two hundred twenty-one billion, two hundred twenty million, twenty-two thousand, one hundred twenty-one".