168109011991 has 2 divisors, whose sum is σ = 168109011992. Its totient is φ = 168109011990.

The previous prime is 168109011979. The next prime is 168109012009. The reversal of 168109011991 is 199110901861.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 168109011991 - 2²⁷ = 167974794263 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (168109021991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 84054505995 + 84054505996.

It is an arithmetic number, because the mean of its divisors is an integer number (84054505996).

Almost surely, 2^168109011991 is an apocalyptic number.

168109011991 is a deficient number, since it is larger than the sum of its proper divisors (1).

168109011991 is an equidigital number, since it uses as much as digits as its factorization.

168109011991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34992, while the sum is 46.

The spelling of 168109011991 in words is "one hundred sixty-eight billion, one hundred nine million, eleven thousand, nine hundred ninety-one".