18099209 has 2 divisors, whose sum is σ = 18099210. Its totient is φ = 18099208.

The previous prime is 18099199. The next prime is 18099217. The reversal of 18099209 is 90299081.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10259209 + 7840000 = 3203^2 + 2800^2 .

It is a cyclic number.

It is not a de Polignac number, because 18099209 - 2²⁰ = 17050633 is a prime.

It is not a weakly prime, because it can be changed into another prime (18099269) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9049604 + 9049605.

It is an arithmetic number, because the mean of its divisors is an integer number (9049605).

Almost surely, 2^18099209 is an apocalyptic number.

It is an amenable number.

18099209 is a deficient number, since it is larger than the sum of its proper divisors (1).

18099209 is an equidigital number, since it uses as much as digits as its factorization.

18099209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11664, while the sum is 38.

The square root of 18099209 is about 4254.3165138480. The cubic root of 18099209 is about 262.5547411158.

The spelling of 18099209 in words is "eighteen million, ninety-nine thousand, two hundred nine".