21200100000991 has 2 divisors, whose sum is σ = 21200100000992. Its totient is φ = 21200100000990.

The previous prime is 21200100000953. The next prime is 21200100001027. The reversal of 21200100000991 is 19900000100212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21200100000991 - 2¹¹ = 21200099998943 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21200100000091) 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, 10600050000495 + 10600050000496.

It is an arithmetic number, because the mean of its divisors is an integer number (10600050000496).

Almost surely, 2^{21200100000991} is an apocalyptic number.

21200100000991 is a deficient number, since it is larger than the sum of its proper divisors (1).

21200100000991 is an equidigital number, since it uses as much as digits as its factorization.

21200100000991 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 25.

The spelling of 21200100000991 in words is "twenty-one trillion, two hundred billion, one hundred million, nine hundred ninety-one", and thus it is an aban number.