2112121021 has 4 divisors (see below), whose sum is σ = 2236363452. Its totient is φ = 1987878592.

The previous prime is 2112121007. The next prime is 2112121049. The reversal of 2112121021 is 1201212112.

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 1915812900 + 196308121 = 43770^2 + 14011^2 .

It is a cyclic number.

It is not a de Polignac number, because 2112121021 - 2⁷ = 2112120893 is a prime.

It is a super-2 number, since 2×2112121021² = 8922110414700164882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2112120992 and 2112121010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2112121091) 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, 62121190 + ... + 62121223.

It is an arithmetic number, because the mean of its divisors is an integer number (559090863).

Almost surely, 2^2112121021 is an apocalyptic number.

It is an amenable number.

2112121021 is a deficient number, since it is larger than the sum of its proper divisors (124242431).

2112121021 is a wasteful number, since it uses less digits than its factorization.

2112121021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124242430.

The product of its (nonzero) digits is 16, while the sum is 13.

The square root of 2112121021 is about 45957.8178441927. The cubic root of 2112121021 is about 1283.0382377810.

Adding to 2112121021 its reverse (1201212112), we get a palindrome (3313333133).

The spelling of 2112121021 in words is "two billion, one hundred twelve million, one hundred twenty-one thousand, twenty-one".