18081817 has 6 divisors (see below), whose sum is σ = 19579902. Its totient is φ = 16690752.

The previous prime is 18081781. The next prime is 18081821. The reversal of 18081817 is 71818081.

It can be written as a sum of positive squares in 3 ways, for example, as 2368521 + 15713296 = 1539^2 + 3964^2 .

It is not a de Polignac number, because 18081817 - 2⁷ = 18081689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18085817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 53328 + ... + 53665.

It is an arithmetic number, because the mean of its divisors is an integer number (3263317).

Almost surely, 2^18081817 is an apocalyptic number.

It is an amenable number.

18081817 is a deficient number, since it is larger than the sum of its proper divisors (1498085).

18081817 is a wasteful number, since it uses less digits than its factorization.

18081817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107019 (or 107006 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 34.

The square root of 18081817 is about 4252.2719809532. The cubic root of 18081817 is about 262.4706156073.

Adding to 18081817 its reverse (71818081), we get a palindrome (89899898).

The spelling of 18081817 in words is "eighteen million, eighty-one thousand, eight hundred seventeen".