18207809 has 2 divisors, whose sum is σ = 18207810. Its totient is φ = 18207808.

The previous prime is 18207797. The next prime is 18207857. The reversal of 18207809 is 90870281.

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., 17247409 + 960400 = 4153^2 + 980^2 .

It is a cyclic number.

It is not a de Polignac number, because 18207809 - 2¹⁶ = 18142273 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18207859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9103904 + 9103905.

It is an arithmetic number, because the mean of its divisors is an integer number (9103905).

Almost surely, 2^18207809 is an apocalyptic number.

It is an amenable number.

18207809 is a deficient number, since it is larger than the sum of its proper divisors (1).

18207809 is an equidigital number, since it uses as much as digits as its factorization.

18207809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8064, while the sum is 35.

The square root of 18207809 is about 4267.0609323046. The cubic root of 18207809 is about 263.0788267236.

The spelling of 18207809 in words is "eighteen million, two hundred seven thousand, eight hundred nine".