221020122121 has 4 divisors (see below), whose sum is σ = 230629692672. Its totient is φ = 211410551572.

The previous prime is 221020122097. The next prime is 221020122137. The reversal of 221020122121 is 121221020122.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 121221020122 = 2 ⋅60610510061.

It is a cyclic number.

It is not a de Polignac number, because 221020122121 - 2²³ = 221011733513 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221020122095 and 221020122104.

It is not an unprimeable number, because it can be changed into a prime (221020122161) 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, 4804785241 + ... + 4804785286.

It is an arithmetic number, because the mean of its divisors is an integer number (57657423168).

Almost surely, 2^221020122121 is an apocalyptic number.

It is an amenable number.

221020122121 is a deficient number, since it is larger than the sum of its proper divisors (9609570551).

221020122121 is an equidigital number, since it uses as much as digits as its factorization.

221020122121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9609570550.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 221020122121 its reverse (121221020122), we get a palindrome (342241142243).

It can be divided in two parts, 221020122 and 121, that multiplied together give a palindrome (26743434762).

The spelling of 221020122121 in words is "two hundred twenty-one billion, twenty million, one hundred twenty-two thousand, one hundred twenty-one".