113581 has 4 divisors (see below), whose sum is σ = 122332. Its totient is φ = 104832.

The previous prime is 113567. The next prime is 113591. The reversal of 113581 is 185311.

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

It can be written as a sum of positive squares in 2 ways, for example, as 28900 + 84681 = 170^2 + 291^2 .

It is not a de Polignac number, because 113581 - 2⁷ = 113453 is a prime.

It is a super-2 number, since 2×113581² = 25801287122, which contains 22 as substring.

It is a Duffinian number.

113581 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (113501) 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, 4356 + ... + 4381.

It is an arithmetic number, because the mean of its divisors is an integer number (30583).

2¹¹³⁵⁸¹ is an apocalyptic number.

It is an amenable number.

113581 is a deficient number, since it is larger than the sum of its proper divisors (8751).

113581 is an equidigital number, since it uses as much as digits as its factorization.

113581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8750.

The product of its digits is 120, while the sum is 19.

The square root of 113581 is about 337.0178036840. The cubic root of 113581 is about 48.4285979478.

Adding to 113581 its reverse (185311), we get a palindrome (298892).

The spelling of 113581 in words is "one hundred thirteen thousand, five hundred eighty-one".