18116809 has 2 divisors, whose sum is σ = 18116810. Its totient is φ = 18116808.

The previous prime is 18116807. The next prime is 18116821. The reversal of 18116809 is 90861181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16426809 + 1690000 = 4053^2 + 1300^2 .

It is an emirp because it is prime and its reverse (90861181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18116809 - 2¹ = 18116807 is a prime.

Together with 18116807, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (18116807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9058404 + 9058405.

It is an arithmetic number, because the mean of its divisors is an integer number (9058405).

Almost surely, 2^18116809 is an apocalyptic number.

It is an amenable number.

18116809 is a deficient number, since it is larger than the sum of its proper divisors (1).

18116809 is an equidigital number, since it uses as much as digits as its factorization.

18116809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3456, while the sum is 34.

The square root of 18116809 is about 4256.3844986091. The cubic root of 18116809 is about 262.6398178801.

The spelling of 18116809 in words is "eighteen million, one hundred sixteen thousand, eight hundred nine".