18091217 has 2 divisors, whose sum is σ = 18091218. Its totient is φ = 18091216.

The previous prime is 18091201. The next prime is 18091243. The reversal of 18091217 is 71219081.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9186961 + 8904256 = 3031^2 + 2984^2 .

It is a cyclic number.

It is not a de Polignac number, because 18091217 - 2⁴ = 18091201 is a prime.

It is a super-3 number, since 3×18091217³ (a number of 23 digits) contains 333 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18091217.

It is not a weakly prime, because it can be changed into another prime (18096217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9045608 + 9045609.

It is an arithmetic number, because the mean of its divisors is an integer number (9045609).

Almost surely, 2^18091217 is an apocalyptic number.

It is an amenable number.

18091217 is a deficient number, since it is larger than the sum of its proper divisors (1).

18091217 is an equidigital number, since it uses as much as digits as its factorization.

18091217 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 29.

The square root of 18091217 is about 4253.3771288236. The cubic root of 18091217 is about 262.5160903213.

The spelling of 18091217 in words is "eighteen million, ninety-one thousand, two hundred seventeen".