91018 has 8 divisors (see below), whose sum is σ = 144612. Its totient is φ = 42816.

The previous prime is 91009. The next prime is 91019. The reversal of 91018 is 81019.

It can be written as a sum of positive squares in 2 ways, for example, as 88209 + 2809 = 297^2 + 53^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 90986 and 91004.

It is not an unprimeable number, because it can be changed into a prime (91019) by changing a digit.

91018 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 3 ways as a sum of consecutive naturals, for example, 1305 + ... + 1372.

2⁹¹⁰¹⁸ is an apocalyptic number.

91018 is a deficient number, since it is larger than the sum of its proper divisors (53594).

91018 is a wasteful number, since it uses less digits than its factorization.

91018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2696.

The product of its (nonzero) digits is 72, while the sum is 19.

The square root of 91018 is about 301.6918958143. The cubic root of 91018 is about 44.9823799329.

Subtracting from 91018 its reverse (81019), we obtain a palindrome (9999).

The spelling of 91018 in words is "ninety-one thousand, eighteen".