2121121221121 has 4 divisors (see below), whose sum is σ = 2424138538432. Its totient is φ = 1818103903812.

The previous prime is 2121121221103. The next prime is 2121121221151. The reversal of 2121121221121 is 1211221211212.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 2121121221121 - 2¹¹ = 2121121219073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2121121221151) 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, 151508658645 + ... + 151508658658.

It is an arithmetic number, because the mean of its divisors is an integer number (606034634608).

Almost surely, 2^{2121121221121} is an apocalyptic number.

It is an amenable number.

2121121221121 is a deficient number, since it is larger than the sum of its proper divisors (303017317311).

2121121221121 is an equidigital number, since it uses as much as digits as its factorization.

2121121221121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 303017317310.

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

Adding to 2121121221121 its reverse (1211221211212), we get a palindrome (3332342432333).

Subtracting from 2121121221121 its reverse (1211221211212), we obtain a palindrome (909900009909).

The spelling of 2121121221121 in words is "two trillion, one hundred twenty-one billion, one hundred twenty-one million, two hundred twenty-one thousand, one hundred twenty-one".