1221222121121 has 16 divisors (see below), whose sum is σ = 1244690254080. Its totient is φ = 1197849317520.

The previous prime is 1221222121087. The next prime is 1221222121151. The reversal of 1221222121121 is 1211212221221.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221222121121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221222121093 and 1221222121102.

It is not an unprimeable number, because it can be changed into a prime (1221222121151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 50646350 + ... + 50670456.

It is an arithmetic number, because the mean of its divisors is an integer number (77793140880).

Almost surely, 2^{1221222121121} is an apocalyptic number.

It is an amenable number.

1221222121121 is a deficient number, since it is larger than the sum of its proper divisors (23468132959).

1221222121121 is a wasteful number, since it uses less digits than its factorization.

1221222121121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26044.

The product of its digits is 128, while the sum is 20.

Adding to 1221222121121 its reverse (1211212221221), we get a palindrome (2432434342342).

The spelling of 1221222121121 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-two million, one hundred twenty-one thousand, one hundred twenty-one".