818181818181817 has 4 divisors (see below), whose sum is σ = 818181878547060. Its totient is φ = 818181757816576.

The previous prime is 818181818181811. The next prime is 818181818181839. The reversal of 818181818181817 is 718181818181818.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 398614641592896 + 419567176588921 = 19965336^2 + 20483339^2 .

It is a cyclic number.

It is not a de Polignac number, because 818181818181817 - 2¹¹ = 818181818179769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (818181818181811) 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, 640713 + ... + 40457065.

It is an arithmetic number, because the mean of its divisors is an integer number (204545469636765).

Almost surely, 2^{818181818181817} is an apocalyptic number.

It is an amenable number.

818181818181817 is a deficient number, since it is larger than the sum of its proper divisors (60365243).

818181818181817 is a wasteful number, since it uses less digits than its factorization.

818181818181817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60365242.

The product of its digits is 14680064, while the sum is 70.

Subtracting from 818181818181817 its reverse (718181818181818), we obtain a palindrome (99999999999999).

It can be divided in two parts, 81818181 and 8181817, that added together give a palindrome (89999998).

The spelling of 818181818181817 in words is "eight hundred eighteen trillion, one hundred eighty-one billion, eight hundred eighteen million, one hundred eighty-one thousand, eight hundred seventeen".