2112221212121 has 4 divisors (see below), whose sum is σ = 2112227279412. Its totient is φ = 2112215144832.

The previous prime is 2112221212117. The next prime is 2112221212147. The reversal of 2112221212121 is 1212121222112.

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 1281141015625 + 831080196496 = 1131875^2 + 911636^2 .

It is a cyclic number.

It is not a de Polignac number, because 2112221212121 - 2² = 2112221212117 is a prime.

It is a super-2 number, since 2×2112221212121² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2112221212093 and 2112221212102.

It is not an unprimeable number, because it can be changed into a prime (2112221212021) 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, 2477456 + ... + 3219041.

It is an arithmetic number, because the mean of its divisors is an integer number (528056819853).

Almost surely, 2^{2112221212121} is an apocalyptic number.

It is an amenable number.

2112221212121 is a deficient number, since it is larger than the sum of its proper divisors (6067291).

2112221212121 is an equidigital number, since it uses as much as digits as its factorization.

2112221212121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6067290.

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

Adding to 2112221212121 its reverse (1212121222112), we get a palindrome (3324342434233).

Subtracting from 2112221212121 its reverse (1212121222112), we obtain a palindrome (900099990009).

The spelling of 2112221212121 in words is "two trillion, one hundred twelve billion, two hundred twenty-one million, two hundred twelve thousand, one hundred twenty-one".