1221331020121 has 4 divisors (see below), whose sum is σ = 1221387802852. Its totient is φ = 1221274237392.

The previous prime is 1221331020109. The next prime is 1221331020131. The reversal of 1221331020121 is 1210201331221.

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 782934746896 + 438396273225 = 884836^2 + 662115^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221331020121 - 2⁵ = 1221331020089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221331020101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28359090 + ... + 28402123.

It is an arithmetic number, because the mean of its divisors is an integer number (305346950713).

Almost surely, 2^{1221331020121} is an apocalyptic number.

It is an amenable number.

1221331020121 is a deficient number, since it is larger than the sum of its proper divisors (56782731).

1221331020121 is an equidigital number, since it uses as much as digits as its factorization.

1221331020121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56782730.

The product of its (nonzero) digits is 144, while the sum is 19.

Adding to 1221331020121 its reverse (1210201331221), we get a palindrome (2431532351342).

The spelling of 1221331020121 in words is "one trillion, two hundred twenty-one billion, three hundred thirty-one million, twenty thousand, one hundred twenty-one".