2121112121 has 4 divisors (see below), whose sum is σ = 2121204852. Its totient is φ = 2121019392.

The previous prime is 2121112093. The next prime is 2121112157. The reversal of 2121112121 is 1212111212.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 1525996096 + 595116025 = 39064^2 + 24395^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121112121 - 2⁶ = 2121112057 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2121112096 and 2121112105.

It is not an unprimeable number, because it can be changed into a prime (2121112181) 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 3 ways as a sum of consecutive naturals, for example, 15161 + ... + 66873.

It is an arithmetic number, because the mean of its divisors is an integer number (530301213).

Almost surely, 2^2121112121 is an apocalyptic number.

It is an amenable number.

2121112121 is a deficient number, since it is larger than the sum of its proper divisors (92731).

2121112121 is an equidigital number, since it uses as much as digits as its factorization.

2121112121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92730.

The product of its digits is 16, while the sum is 14.

The square root of 2121112121 is about 46055.5330117891. The cubic root of 2121112121 is about 1284.8562514385.

Adding to 2121112121 its reverse (1212111212), we get a palindrome (3333223333).

Subtracting from 2121112121 its reverse (1212111212), we obtain a palindrome (909000909).

The spelling of 2121112121 in words is "two billion, one hundred twenty-one million, one hundred twelve thousand, one hundred twenty-one".