1221201121121 has 4 divisors (see below), whose sum is σ = 1221216944532. Its totient is φ = 1221185297712.

The previous prime is 1221201121099. The next prime is 1221201121187. The reversal of 1221201121121 is 1211211021221.

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 780464466721 + 440736654400 = 883439^2 + 663880^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221201121121 - 2⁶ = 1221201121057 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221201121121.

It is not an unprimeable number, because it can be changed into a prime (1221201621121) 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, 7795370 + ... + 7950483.

It is an arithmetic number, because the mean of its divisors is an integer number (305304236133).

Almost surely, 2^{1221201121121} is an apocalyptic number.

It is an amenable number.

1221201121121 is a deficient number, since it is larger than the sum of its proper divisors (15823411).

1221201121121 is an equidigital number, since it uses as much as digits as its factorization.

1221201121121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15823410.

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

Adding to 1221201121121 its reverse (1211211021221), we get a palindrome (2432412142342).

The spelling of 1221201121121 in words is "one trillion, two hundred twenty-one billion, two hundred one million, one hundred twenty-one thousand, one hundred twenty-one".