221020121011121 has 4 divisors (see below), whose sum is σ = 221774455895412. Its totient is φ = 220265786126832.

The previous prime is 221020121011103. The next prime is 221020121011133. The reversal of 221020121011121 is 121110121020122.

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 198061600846096 + 22958520165025 = 14073436^2 + 4791505^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221020121011121 is a prime.

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 221020121011121.

It is not an unprimeable number, because it can be changed into a prime (221020121011721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 377167441706 + ... + 377167442291.

It is an arithmetic number, because the mean of its divisors is an integer number (55443613973853).

Almost surely, 2^{221020121011121} is an apocalyptic number.

It is an amenable number.

221020121011121 is a deficient number, since it is larger than the sum of its proper divisors (754334884291).

221020121011121 is an equidigital number, since it uses as much as digits as its factorization.

221020121011121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 754334884290.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 221020121011121 its reverse (121110121020122), we get a palindrome (342130242031243).

Subtracting from 221020121011121 its reverse (121110121020122), we obtain a palindrome (99909999990999).

The spelling of 221020121011121 in words is "two hundred twenty-one trillion, twenty billion, one hundred twenty-one million, eleven thousand, one hundred twenty-one".