1221313321121 has 4 divisors (see below), whose sum is σ = 1221323953044. Its totient is φ = 1221302689200.

The previous prime is 1221313321073. The next prime is 1221313321181. The reversal of 1221313321121 is 1211233131221.

It is a happy number.

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 161877475600 + 1059435845521 = 402340^2 + 1029289^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221313321121 - 2¹⁴ = 1221313304737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221313321181) 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, 5141750 + ... + 5374031.

It is an arithmetic number, because the mean of its divisors is an integer number (305330988261).

Almost surely, 2^{1221313321121} is an apocalyptic number.

It is an amenable number.

1221313321121 is a deficient number, since it is larger than the sum of its proper divisors (10631923).

1221313321121 is a wasteful number, since it uses less digits than its factorization.

1221313321121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10631922.

The product of its digits is 432, while the sum is 23.

Adding to 1221313321121 its reverse (1211233131221), we get a palindrome (2432546452342).

The spelling of 1221313321121 in words is "one trillion, two hundred twenty-one billion, three hundred thirteen million, three hundred twenty-one thousand, one hundred twenty-one".