1221211121121 has 48 divisors (see below), whose sum is σ = 1854374311680. Its totient is φ = 794292683040.

The previous prime is 1221211121111. The next prime is 1221211121131. The reversal of 1221211121121 is 1211211121221.

It is a happy number.

1221211121121 is a `hidden beast` number, since 1 + 221 + 211 + 1 + 211 + 21 = 666.

It is an interprime number because it is at equal distance from previous prime (1221211121111) and next prime (1221211121131).

It is not a de Polignac number, because 1221211121121 - 2³³ = 1212621186529 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1221211121094 and 1221211121103.

It is not an unprimeable number, because it can be changed into a prime (1221211121111) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 18874536 + ... + 18939126.

It is an arithmetic number, because the mean of its divisors is an integer number (38632798160).

Almost surely, 2^{1221211121121} is an apocalyptic number.

It is an amenable number.

1221211121121 is a deficient number, since it is larger than the sum of its proper divisors (633163190559).

1221211121121 is an equidigital number, since it uses as much as digits as its factorization.

1221211121121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65011 (or 64958 counting only the distinct ones).

The product of its digits is 32, while the sum is 18.

Adding to 1221211121121 its reverse (1211211121221), we get a palindrome (2432422242342).

The spelling of 1221211121121 in words is "one trillion, two hundred twenty-one billion, two hundred eleven million, one hundred twenty-one thousand, one hundred twenty-one".