21100110091 has 2 divisors, whose sum is σ = 21100110092. Its totient is φ = 21100110090.

The previous prime is 21100110077. The next prime is 21100110107. The reversal of 21100110091 is 19001100112.

It is an a-pointer prime, because the next prime (21100110107) can be obtained adding 21100110091 to its sum of digits (16).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21100110091 - 2²¹ = 21098012939 is a prime.

It is not a weakly prime, because it can be changed into another prime (21100110791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550055045 + 10550055046.

It is an arithmetic number, because the mean of its divisors is an integer number (10550055046).

Almost surely, 2^21100110091 is an apocalyptic number.

21100110091 is a deficient number, since it is larger than the sum of its proper divisors (1).

21100110091 is an equidigital number, since it uses as much as digits as its factorization.

21100110091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18, while the sum is 16.

The spelling of 21100110091 in words is "twenty-one billion, one hundred million, one hundred ten thousand, ninety-one".