91109666993 has 2 divisors, whose sum is σ = 91109666994. Its totient is φ = 91109666992.

The previous prime is 91109666981. The next prime is 91109667001. The reversal of 91109666993 is 39966690119.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 71169967729 + 19939699264 = 266777^2 + 141208^2 .

It is a cyclic number.

It is not a de Polignac number, because 91109666993 - 2¹⁴ = 91109650609 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (91109666953) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45554833496 + 45554833497.

It is an arithmetic number, because the mean of its divisors is an integer number (45554833497).

Almost surely, 2^91109666993 is an apocalyptic number.

It is an amenable number.

91109666993 is a deficient number, since it is larger than the sum of its proper divisors (1).

91109666993 is an equidigital number, since it uses as much as digits as its factorization.

91109666993 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4251528, while the sum is 59.

The spelling of 91109666993 in words is "ninety-one billion, one hundred nine million, six hundred sixty-six thousand, nine hundred ninety-three".