116581 has 4 divisors (see below), whose sum is σ = 118252. Its totient is φ = 114912.

The previous prime is 116579. The next prime is 116593. The reversal of 116581 is 185611.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 185611 = 19 ⋅9769.

It can be written as a sum of positive squares in 2 ways, for example, as 43681 + 72900 = 209^2 + 270^2 .

It is a cyclic number.

It is not a de Polignac number, because 116581 - 2¹ = 116579 is a prime.

It is a super-2 number, since 2×116581² = 27182259122, which contains 22 as substring.

It is a Duffinian number.

116581 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (116531) 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, 726 + ... + 871.

It is an arithmetic number, because the mean of its divisors is an integer number (29563).

2¹¹⁶⁵⁸¹ is an apocalyptic number.

It is an amenable number.

116581 is a deficient number, since it is larger than the sum of its proper divisors (1671).

116581 is an equidigital number, since it uses as much as digits as its factorization.

116581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1670.

The product of its digits is 240, while the sum is 22.

The square root of 116581 is about 341.4395993437. The cubic root of 116581 is about 48.8512775077.

The spelling of 116581 in words is "one hundred sixteen thousand, five hundred eighty-one".