21210212121211 has 2 divisors, whose sum is σ = 21210212121212. Its totient is φ = 21210212121210.

The previous prime is 21210212121209. The next prime is 21210212121221. The reversal of 21210212121211 is 11212121201212.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21210212121211 - 2¹ = 21210212121209 is a prime.

It is a super-2 number, since 2×21210212121211² (a number of 27 digits) contains 22 as substring.

Together with 21210212121209, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21210212121221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605106060605 + 10605106060606.

It is an arithmetic number, because the mean of its divisors is an integer number (10605106060606).

Almost surely, 2^{21210212121211} is an apocalyptic number.

21210212121211 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210212121211 is an equidigital number, since it uses as much as digits as its factorization.

21210212121211 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 21210212121211 its reverse (11212121201212), we get a palindrome (32422333322423).

The spelling of 21210212121211 in words is "twenty-one trillion, two hundred ten billion, two hundred twelve million, one hundred twenty-one thousand, two hundred eleven".