9581 has 8 divisors (see below), whose sum is σ = 11424. Its totient is φ = 7920.

The previous prime is 9551. The next prime is 9587. The reversal of 9581 is 1859.

9581 is nontrivially palindromic in base 12.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-9581 is a prime.

It is a super-2 number, since 2×9581² = 183591122, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 8 and base 16.

It is a nialpdrome in base 11.

It is a zygodrome in base 8.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 9581.

It is not an unprimeable number, because it can be changed into a prime (9587) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 110 + ... + 176.

It is an arithmetic number, because the mean of its divisors is an integer number (1428).

2⁹⁵⁸¹ is an apocalyptic number.

It is an amenable number.

9581 is a deficient number, since it is larger than the sum of its proper divisors (1843).

9581 is a wasteful number, since it uses less digits than its factorization.

9581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91.

The product of its digits is 360, while the sum is 23.

The square root of 9581 is about 97.8825827203. The cubic root of 9581 is about 21.2391409339.

Adding to 9581 its sum of digits (23), we get a square (9604 = 98²).

It can be divided in two parts, 958 and 1, that added together give a palindrome (959).

The spelling of 9581 in words is "nine thousand, five hundred eighty-one".