18717888291691 has 2 divisors, whose sum is σ = 18717888291692. Its totient is φ = 18717888291690.

The previous prime is 18717888291671. The next prime is 18717888291749. The reversal of 18717888291691 is 19619288871781.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18717888291691 is a prime.

It is not a weakly prime, because it can be changed into another prime (18717888291671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9358944145845 + 9358944145846.

It is an arithmetic number, because the mean of its divisors is an integer number (9358944145846).

Almost surely, 2^{18717888291691} is an apocalyptic number.

18717888291691 is a deficient number, since it is larger than the sum of its proper divisors (1).

18717888291691 is an equidigital number, since it uses as much as digits as its factorization.

18717888291691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 195084288, while the sum is 76.

The spelling of 18717888291691 in words is "eighteen trillion, seven hundred seventeen billion, eight hundred eighty-eight million, two hundred ninety-one thousand, six hundred ninety-one".