18366809 has 2 divisors, whose sum is σ = 18366810. Its totient is φ = 18366808.

The previous prime is 18366793. The next prime is 18366833. The reversal of 18366809 is 90866381.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14478025 + 3888784 = 3805^2 + 1972^2 .

It is a cyclic number.

It is not a de Polignac number, because 18366809 - 2⁴ = 18366793 is a prime.

It is not a weakly prime, because it can be changed into another prime (18366839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9183404 + 9183405.

It is an arithmetic number, because the mean of its divisors is an integer number (9183405).

Almost surely, 2^18366809 is an apocalyptic number.

It is an amenable number.

18366809 is a deficient number, since it is larger than the sum of its proper divisors (1).

18366809 is an equidigital number, since it uses as much as digits as its factorization.

18366809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 62208, while the sum is 41.

The square root of 18366809 is about 4285.6515257309. The cubic root of 18366809 is about 263.8423885136.

The spelling of 18366809 in words is "eighteen million, three hundred sixty-six thousand, eight hundred nine".