212121212021 has 2 divisors, whose sum is σ = 212121212022. Its totient is φ = 212121212020.

The previous prime is 212121211987. The next prime is 212121212101. The reversal of 212121212021 is 120212121212.

212121212021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 187349599921 + 24771612100 = 432839^2 + 157390^2 .

It is a cyclic number.

It is not a de Polignac number, because 212121212021 - 2⁶ = 212121211957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212121211021) 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 as a sum of consecutive naturals, namely, 106060606010 + 106060606011.

It is an arithmetic number, because the mean of its divisors is an integer number (106060606011).

Almost surely, 2^212121212021 is an apocalyptic number.

It is an amenable number.

212121212021 is a deficient number, since it is larger than the sum of its proper divisors (1).

212121212021 is an equidigital number, since it uses as much as digits as its factorization.

212121212021 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 212121212021 its reverse (120212121212), we get a palindrome (332333333233).

The spelling of 212121212021 in words is "two hundred twelve billion, one hundred twenty-one million, two hundred twelve thousand, twenty-one".