91720 has 16 divisors (see below), whose sum is σ = 206460. Its totient is φ = 36672.

The previous prime is 91711. The next prime is 91733. The reversal of 91720 is 2719.

It can be written as a sum of positive squares in 2 ways, for example, as 88804 + 2916 = 298^2 + 54^2 .

It is an unprimeable 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 3 ways as a sum of consecutive naturals, for example, 1107 + ... + 1186.

2⁹¹⁷²⁰ is an apocalyptic number.

It is an amenable number.

91720 is an abundant number, since it is smaller than the sum of its proper divisors (114740).

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 (103230).

91720 is a wasteful number, since it uses less digits than its factorization.

91720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2304 (or 2300 counting only the distinct ones).

The product of its (nonzero) digits is 126, while the sum is 19.

The square root of 91720 is about 302.8530997035. The cubic root of 91720 is about 45.0977299854.

The spelling of 91720 in words is "ninety-one thousand, seven hundred twenty".