91818 has 12 divisors (see below), whose sum is σ = 198978. Its totient is φ = 30600.

The previous prime is 91813. The next prime is 91823. The reversal of 91818 is 81819.

It is an interprime number because it is at equal distance from previous prime (91813) and next prime (91823).

It can be written as a sum of positive squares in only one way, i.e., 91809 + 9 = 303^2 + 3^2 .

It is a Curzon number.

It is a plaindrome in base 14 and base 16.

It is a junction number, because it is equal to n+sod(n) for n = 91791 and 91800.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 91818.

It is not an unprimeable number, because it can be changed into a prime (91811) by changing a digit.

91818 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2533 + ... + 2568.

2⁹¹⁸¹⁸ is an apocalyptic number.

91818 is an abundant number, since it is smaller than the sum of its proper divisors (107160).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

91818 is a wasteful number, since it uses less digits than its factorization.

91818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5109 (or 5106 counting only the distinct ones).

The product of its digits is 576, while the sum is 27.

The square root of 91818 is about 303.0148511212. The cubic root of 91818 is about 45.1137861142.

Subtracting from 91818 its reverse (81819), we obtain a palindrome (9999).

It can be divided in two parts, 91 and 818, that added together give a palindrome (909).

The spelling of 91818 in words is "ninety-one thousand, eight hundred eighteen".