91918 has 4 divisors (see below), whose sum is σ = 137880. Its totient is φ = 45958.

The previous prime is 91909. The next prime is 91921. The reversal of 91918 is 81919.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 22978 + ... + 22981.

It is an arithmetic number, because the mean of its divisors is an integer number (34470).

2⁹¹⁹¹⁸ is an apocalyptic number.

91918 is a deficient number, since it is larger than the sum of its proper divisors (45962).

91918 is a wasteful number, since it uses less digits than its factorization.

91918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45961.

The product of its digits is 648, while the sum is 28.

The square root of 91918 is about 303.1798146315. The cubic root of 91918 is about 45.1301581466.

Subtracting from 91918 its reverse (81919), we obtain a palindrome (9999).

It can be divided in two parts, 91 and 918, that multiplied together give a palindrome (83538).

The spelling of 91918 in words is "ninety-one thousand, nine hundred eighteen".