21100191911 has 2 divisors, whose sum is σ = 21100191912. Its totient is φ = 21100191910.

The previous prime is 21100191899. The next prime is 21100191913. The reversal of 21100191911 is 11919100112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21100191911 - 2³⁴ = 3920322727 is a prime.

Together with 21100191913, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21100191913) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550095955 + 10550095956.

It is an arithmetic number, because the mean of its divisors is an integer number (10550095956).

Almost surely, 2^21100191911 is an apocalyptic number.

21100191911 is a deficient number, since it is larger than the sum of its proper divisors (1).

21100191911 is an equidigital number, since it uses as much as digits as its factorization.

21100191911 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 162, while the sum is 26.

The spelling of 21100191911 in words is "twenty-one billion, one hundred million, one hundred ninety-one thousand, nine hundred eleven".