18317987 has 2 divisors, whose sum is σ = 18317988. Its totient is φ = 18317986.

The previous prime is 18317983. The next prime is 18317989. The reversal of 18317987 is 78971381.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18317987 - 2² = 18317983 is a prime.

Together with 18317989, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18317983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9158993 + 9158994.

It is an arithmetic number, because the mean of its divisors is an integer number (9158994).

Almost surely, 2^18317987 is an apocalyptic number.

18317987 is a deficient number, since it is larger than the sum of its proper divisors (1).

18317987 is an equidigital number, since it uses as much as digits as its factorization.

18317987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 84672, while the sum is 44.

The square root of 18317987 is about 4279.9517520645. The cubic root of 18317987 is about 263.6084022412.

The spelling of 18317987 in words is "eighteen million, three hundred seventeen thousand, nine hundred eighty-seven".