221220112121 has 4 divisors (see below), whose sum is σ = 221478246132. Its totient is φ = 220961978112.

The previous prime is 221220112103. The next prime is 221220112151. The reversal of 221220112121 is 121211022122.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 199084623721 + 22135488400 = 446189^2 + 148780^2 .

It is a cyclic number.

It is not a de Polignac number, because 221220112121 - 2¹⁴ = 221220095737 is a prime.

It is a super-2 number, since 2×221220112121² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 221220112121.

It is not an unprimeable number, because it can be changed into a prime (221220112151) 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, 129065720 + ... + 129067433.

It is an arithmetic number, because the mean of its divisors is an integer number (55369561533).

Almost surely, 2^221220112121 is an apocalyptic number.

It is an amenable number.

221220112121 is a deficient number, since it is larger than the sum of its proper divisors (258134011).

221220112121 is an equidigital number, since it uses as much as digits as its factorization.

221220112121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258134010.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 221220112121 its reverse (121211022122), we get a palindrome (342431134243).

The spelling of 221220112121 in words is "two hundred twenty-one billion, two hundred twenty million, one hundred twelve thousand, one hundred twenty-one".