21211102212121 has 2 divisors, whose sum is σ = 21211102212122. Its totient is φ = 21211102212120.

The previous prime is 21211102212089. The next prime is 21211102212163. The reversal of 21211102212121 is 12121220111212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13019027859721 + 8192074352400 = 3608189^2 + 2862180^2 .

It is a cyclic number.

It is not a de Polignac number, because 21211102212121 - 2⁵ = 21211102212089 is a prime.

It is not a weakly prime, because it can be changed into another prime (21211102212191) 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, 10605551106060 + 10605551106061.

It is an arithmetic number, because the mean of its divisors is an integer number (10605551106061).

Almost surely, 2^{21211102212121} is an apocalyptic number.

It is an amenable number.

21211102212121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21211102212121 is an equidigital number, since it uses as much as digits as its factorization.

21211102212121 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 19.

Adding to 21211102212121 its reverse (12121220111212), we get a palindrome (33332322323333).

The spelling of 21211102212121 in words is "twenty-one trillion, two hundred eleven billion, one hundred two million, two hundred twelve thousand, one hundred twenty-one".