21211201211111 has 2 divisors, whose sum is σ = 21211201211112. Its totient is φ = 21211201211110.

The previous prime is 21211201211089. The next prime is 21211201211113. The reversal of 21211201211111 is 11111210211212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21211201211111 - 2⁴² = 16813154700007 is a prime.

It is a Sophie Germain prime.

Together with 21211201211113, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21211201211111.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21211201211113) 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, 10605600605555 + 10605600605556.

It is an arithmetic number, because the mean of its divisors is an integer number (10605600605556).

Almost surely, 2^{21211201211111} is an apocalyptic number.

21211201211111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21211201211111 is an equidigital number, since it uses as much as digits as its factorization.

21211201211111 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16, while the sum is 17.

Adding to 21211201211111 its reverse (11111210211212), we get a palindrome (32322411422323).

The spelling of 21211201211111 in words is "twenty-one trillion, two hundred eleven billion, two hundred one million, two hundred eleven thousand, one hundred eleven".