111111111000991 has 2 divisors, whose sum is σ = 111111111000992. Its totient is φ = 111111111000990.

The previous prime is 111111111000949. The next prime is 111111111001021. The reversal of 111111111000991 is 199000111111111.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 111111111000991 - 2¹³ = 111111110992799 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111111111000941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55555555500495 + 55555555500496.

It is an arithmetic number, because the mean of its divisors is an integer number (55555555500496).

Almost surely, 2^{111111111000991} is an apocalyptic number.

111111111000991 is a deficient number, since it is larger than the sum of its proper divisors (1).

111111111000991 is an equidigital number, since it uses as much as digits as its factorization.

111111111000991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 81, while the sum is 28.

The spelling of 111111111000991 in words is "one hundred eleven trillion, one hundred eleven billion, one hundred eleven million, nine hundred ninety-one", and thus it is an aban number.