18065809 has 2 divisors, whose sum is σ = 18065810. Its totient is φ = 18065808.

The previous prime is 18065767. The next prime is 18065819. The reversal of 18065809 is 90856081.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17977600 + 88209 = 4240^2 + 297^2 .

It is a cyclic number.

It is not a de Polignac number, because 18065809 - 2⁷ = 18065681 is a prime.

It is not a weakly prime, because it can be changed into another prime (18065819) 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, 9032904 + 9032905.

It is an arithmetic number, because the mean of its divisors is an integer number (9032905).

Almost surely, 2^18065809 is an apocalyptic number.

It is an amenable number.

18065809 is a deficient number, since it is larger than the sum of its proper divisors (1).

18065809 is an equidigital number, since it uses as much as digits as its factorization.

18065809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17280, while the sum is 37.

The square root of 18065809 is about 4250.3892762899. The cubic root of 18065809 is about 262.3931368499.

The spelling of 18065809 in words is "eighteen million, sixty-five thousand, eight hundred nine".