91168651997 has 2 divisors, whose sum is σ = 91168651998. Its totient is φ = 91168651996.

The previous prime is 91168651883. The next prime is 91168652023. The reversal of 91168651997 is 79915686119.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 62587030276 + 28581621721 = 250174^2 + 169061^2 .

It is a cyclic number.

It is not a de Polignac number, because 91168651997 - 2²⁶ = 91101543133 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91168659997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45584325998 + 45584325999.

It is an arithmetic number, because the mean of its divisors is an integer number (45584325999).

Almost surely, 2^91168651997 is an apocalyptic number.

It is an amenable number.

91168651997 is a deficient number, since it is larger than the sum of its proper divisors (1).

91168651997 is an equidigital number, since it uses as much as digits as its factorization.

91168651997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7348320, while the sum is 62.

The spelling of 91168651997 in words is "ninety-one billion, one hundred sixty-eight million, six hundred fifty-one thousand, nine hundred ninety-seven".