21001102110991 has 2 divisors, whose sum is σ = 21001102110992. Its totient is φ = 21001102110990.

The previous prime is 21001102110953. The next prime is 21001102111009. The reversal of 21001102110991 is 19901120110012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21001102110991 - 2²⁹ = 21000565240079 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21001102110491) 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, 10500551055495 + 10500551055496.

It is an arithmetic number, because the mean of its divisors is an integer number (10500551055496).

Almost surely, 2^{21001102110991} is an apocalyptic number.

21001102110991 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001102110991 is an equidigital number, since it uses as much as digits as its factorization.

21001102110991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 324, while the sum is 28.

The spelling of 21001102110991 in words is "twenty-one trillion, one billion, one hundred two million, one hundred ten thousand, nine hundred ninety-one".