91218 has 16 divisors (see below), whose sum is σ = 190656. Its totient is φ = 29040.

The previous prime is 91199. The next prime is 91229. The reversal of 91218 is 81219.

It is a junction number, because it is equal to n+sod(n) for n = 91194 and 91203.

It is an unprimeable number.

91218 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 193 + ... + 468.

It is an arithmetic number, because the mean of its divisors is an integer number (11916).

2⁹¹²¹⁸ is an apocalyptic number.

91218 is an abundant number, since it is smaller than the sum of its proper divisors (99438).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (95328).

91218 is a wasteful number, since it uses less digits than its factorization.

91218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 689.

The product of its digits is 144, while the sum is 21.

The square root of 91218 is about 302.0231779185. The cubic root of 91218 is about 45.0153034370.

Subtracting from 91218 its reverse (81219), we obtain a palindrome (9999).

The spelling of 91218 in words is "ninety-one thousand, two hundred eighteen".