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 2k-9581 is a prime.
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.
29581 is an apocalyptic number.
It is an amenable number.
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 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).
The spelling of 9581 in words is "nine thousand, five hundred eighty-one".