18518009 has 2 divisors, whose sum is σ = 18518010. Its totient is φ = 18518008.

The previous prime is 18517999. The next prime is 18518033. The reversal of 18518009 is 90081581.

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., 10705984 + 7812025 = 3272^2 + 2795^2 .

It is an emirp because it is prime and its reverse (90081581) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18518009 - 2⁸ = 18517753 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18518039) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9259004 + 9259005.

It is an arithmetic number, because the mean of its divisors is an integer number (9259005).

Almost surely, 2^18518009 is an apocalyptic number.

It is an amenable number.

18518009 is a deficient number, since it is larger than the sum of its proper divisors (1).

18518009 is an equidigital number, since it uses as much as digits as its factorization.

18518009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2880, while the sum is 32.

The square root of 18518009 is about 4303.2556280100. The cubic root of 18518009 is about 264.5644155417.

The spelling of 18518009 in words is "eighteen million, five hundred eighteen thousand, nine".