1221203110121 has 4 divisors (see below), whose sum is σ = 1221258258132. Its totient is φ = 1221147962112.

The previous prime is 1221203110109. The next prime is 1221203110181. The reversal of 1221203110121 is 1210113021221.

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 64640520025 + 1156562590096 = 254245^2 + 1075436^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221203110121 - 2¹⁰ = 1221203109097 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 1221203110121.

It is not an unprimeable number, because it can be changed into a prime (1221203110181) 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, 27540776 + ... + 27585081.

It is an arithmetic number, because the mean of its divisors is an integer number (305314564533).

Almost surely, 2^{1221203110121} is an apocalyptic number.

It is an amenable number.

1221203110121 is a deficient number, since it is larger than the sum of its proper divisors (55148011).

1221203110121 is an equidigital number, since it uses as much as digits as its factorization.

1221203110121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55148010.

The product of its (nonzero) digits is 48, while the sum is 17.

Adding to 1221203110121 its reverse (1210113021221), we get a palindrome (2431316131342).

The spelling of 1221203110121 in words is "one trillion, two hundred twenty-one billion, two hundred three million, one hundred ten thousand, one hundred twenty-one".