12509 has 4 divisors (see below), whose sum is σ = 14304. Its totient is φ = 10716.

The previous prime is 12503. The next prime is 12511. The reversal of 12509 is 90521.

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, and also an emirpimes, since its reverse is a distinct semiprime: 90521 = 131 ⋅691.

It is a cyclic number.

It is not a de Polignac number, because 12509 - 2⁸ = 12253 is a prime.

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

It is a Duffinian number.

It is a nialpdrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12503) 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, 887 + ... + 900.

It is an arithmetic number, because the mean of its divisors is an integer number (3576).

2¹²⁵⁰⁹ is an apocalyptic number.

It is an amenable number.

12509 is a deficient number, since it is larger than the sum of its proper divisors (1795).

12509 is an equidigital number, since it uses as much as digits as its factorization.

12509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1794.

The product of its (nonzero) digits is 90, while the sum is 17.

The square root of 12509 is about 111.8436408563. The cubic root of 12509 is about 23.2135127384.

The spelling of 12509 in words is "twelve thousand, five hundred nine".