317899991 has 2 divisors, whose sum is σ = 317899992. Its totient is φ = 317899990.

The previous prime is 317899987. The next prime is 317900021. The reversal of 317899991 is 199998713.

It is a weak prime.

It is an emirp because it is prime and its reverse (199998713) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 317899991 - 2² = 317899987 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (317899931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 158949995 + 158949996.

It is an arithmetic number, because the mean of its divisors is an integer number (158949996).

Almost surely, 2^317899991 is an apocalyptic number.

317899991 is a deficient number, since it is larger than the sum of its proper divisors (1).

317899991 is an equidigital number, since it uses as much as digits as its factorization.

317899991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1102248, while the sum is 56.

The square root of 317899991 is about 17829.7501665054. The cubic root of 317899991 is about 682.4908582906.

The spelling of 317899991 in words is "three hundred seventeen million, eight hundred ninety-nine thousand, nine hundred ninety-one".