191082000991 has 4 divisors (see below), whose sum is σ = 218379429712. Its totient is φ = 163784572272.

The previous prime is 191082000979. The next prime is 191082001009. The reversal of 191082000991 is 199000280191.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 191082000991 - 2¹⁷ = 191081869919 is a prime.

It is a super-2 number, since 2×191082000991² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191082006991) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13648714350 + ... + 13648714363.

It is an arithmetic number, because the mean of its divisors is an integer number (54594857428).

Almost surely, 2^191082000991 is an apocalyptic number.

191082000991 is a deficient number, since it is larger than the sum of its proper divisors (27297428721).

191082000991 is an equidigital number, since it uses as much as digits as its factorization.

191082000991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27297428720.

The product of its (nonzero) digits is 11664, while the sum is 40.

The spelling of 191082000991 in words is "one hundred ninety-one billion, eighty-two million, nine hundred ninety-one", and thus it is an aban number.