18117997223591 has 2 divisors, whose sum is σ = 18117997223592. Its totient is φ = 18117997223590.

The previous prime is 18117997223561. The next prime is 18117997223663. The reversal of 18117997223591 is 19532279971181.

It is a weak prime.

It is an emirp because it is prime and its reverse (19532279971181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18117997223591 - 2¹⁸ = 18117996961447 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18117997223551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9058998611795 + 9058998611796.

It is an arithmetic number, because the mean of its divisors is an integer number (9058998611796).

Almost surely, 2^{18117997223591} is an apocalyptic number.

18117997223591 is a deficient number, since it is larger than the sum of its proper divisors (1).

18117997223591 is an equidigital number, since it uses as much as digits as its factorization.

18117997223591 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17146080, while the sum is 65.

The spelling of 18117997223591 in words is "eighteen trillion, one hundred seventeen billion, nine hundred ninety-seven million, two hundred twenty-three thousand, five hundred ninety-one".