8509 has 4 divisors (see below), whose sum is σ = 8704. Its totient is φ = 8316.

The previous prime is 8501. The next prime is 8513. The reversal of 8509 is 9058.

8509 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 8509 - 2³ = 8501 is a prime.

It is an Ulam number.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 8509.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8501) by changing a digit.

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, 4 + ... + 130.

It is an arithmetic number, because the mean of its divisors is an integer number (2176).

2⁸⁵⁰⁹ is an apocalyptic number.

It is an amenable number.

8509 is a deficient number, since it is larger than the sum of its proper divisors (195).

8509 is a wasteful number, since it uses less digits than its factorization.

8509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 194.

The product of its (nonzero) digits is 360, while the sum is 22.

The square root of 8509 is about 92.2442410127. The cubic root of 8509 is about 20.4154758896.

The spelling of 8509 in words is "eight thousand, five hundred nine".