18006817 has 4 divisors (see below), whose sum is σ = 18025876. Its totient is φ = 17987760.

The previous prime is 18006763. The next prime is 18006839. The reversal of 18006817 is 71860081.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 71860081 = 139 ⋅516979.

It can be written as a sum of positive squares in 2 ways, for example, as 15062161 + 2944656 = 3881^2 + 1716^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18006817 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18006887) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8034 + ... + 10027.

It is an arithmetic number, because the mean of its divisors is an integer number (4506469).

Almost surely, 2^18006817 is an apocalyptic number.

It is an amenable number.

18006817 is a deficient number, since it is larger than the sum of its proper divisors (19059).

18006817 is an equidigital number, since it uses as much as digits as its factorization.

18006817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19058.

The product of its (nonzero) digits is 2688, while the sum is 31.

The square root of 18006817 is about 4243.4440022227. Note that the first 3 decimals coincide. The cubic root of 18006817 is about 262.1072196787.

Adding to 18006817 its reverse (71860081), we get a palindrome (89866898).

The spelling of 18006817 in words is "eighteen million, six thousand, eight hundred seventeen".