1211221221121 has 4 divisors (see below), whose sum is σ = 1211343564244. Its totient is φ = 1211098878000.

The previous prime is 1211221221103. The next prime is 1211221221143.

It is a happy number.

1211221221121 is nontrivially palindromic in base 10.

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 658524135025 + 552697086096 = 811495^2 + 743436^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1211221221121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1211221221191) 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, 61156710 + ... + 61176511.

It is an arithmetic number, because the mean of its divisors is an integer number (302835891061).

Almost surely, 2^{1211221221121} is an apocalyptic number.

It is an amenable number.

1211221221121 is a deficient number, since it is larger than the sum of its proper divisors (122343123).

1211221221121 is an equidigital number, since it uses as much as digits as its factorization.

1211221221121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122343122.

The product of its digits is 64, while the sum is 19.

The spelling of 1211221221121 in words is "one trillion, two hundred eleven billion, two hundred twenty-one million, two hundred twenty-one thousand, one hundred twenty-one".