91911 has 4 divisors (see below), whose sum is σ = 122552. Its totient is φ = 61272.

The previous prime is 91909. The next prime is 91921. The reversal of 91911 is 11919.

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

It is not a de Polignac number, because 91911 - 2¹ = 91909 is a prime.

It is an Ulam number.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91921) 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, 15316 + ... + 15321.

It is an arithmetic number, because the mean of its divisors is an integer number (30638).

2⁹¹⁹¹¹ is an apocalyptic number.

91911 is a deficient number, since it is larger than the sum of its proper divisors (30641).

91911 is a wasteful number, since it uses less digits than its factorization.

91911 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30640.

The product of its digits is 81, while the sum is 21.

The square root of 91911 is about 303.1682701075. The cubic root of 91911 is about 45.1290124910.

The spelling of 91911 in words is "ninety-one thousand, nine hundred eleven".