212120121200021 has 2 divisors, whose sum is σ = 212120121200022. Its totient is φ = 212120121200020.

The previous prime is 212120121200011. The next prime is 212120121200023. The reversal of 212120121200021 is 120002121021212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 207554762511121 + 4565358688900 = 14406761^2 + 2136670^2 .

It is a cyclic number.

It is not a de Polignac number, because 212120121200021 - 2²² = 212120117005717 is a prime.

It is a Sophie Germain prime.

Together with 212120121200023, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212120121200023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106060060600010 + 106060060600011.

It is an arithmetic number, because the mean of its divisors is an integer number (106060060600011).

Almost surely, 2^{212120121200021} is an apocalyptic number.

It is an amenable number.

212120121200021 is a deficient number, since it is larger than the sum of its proper divisors (1).

212120121200021 is an equidigital number, since it uses as much as digits as its factorization.

212120121200021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 212120121200021 its reverse (120002121021212), we get a palindrome (332122242221233).

The spelling of 212120121200021 in words is "two hundred twelve trillion, one hundred twenty billion, one hundred twenty-one million, two hundred thousand, twenty-one".