21111321911 has 2 divisors, whose sum is σ = 21111321912. Its totient is φ = 21111321910.

The previous prime is 21111321901. The next prime is 21111322039. The reversal of 21111321911 is 11912311112.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21111321911 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21111321901) 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, 10555660955 + 10555660956.

It is an arithmetic number, because the mean of its divisors is an integer number (10555660956).

Almost surely, 2^21111321911 is an apocalyptic number.

21111321911 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111321911 is an equidigital number, since it uses as much as digits as its factorization.

21111321911 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 108, while the sum is 23.

The spelling of 21111321911 in words is "twenty-one billion, one hundred eleven million, three hundred twenty-one thousand, nine hundred eleven".