12509309 has 4 divisors (see below), whose sum is σ = 13053216. Its totient is φ = 11965404.

The previous prime is 12509291. The next prime is 12509317. The reversal of 12509309 is 90390521.

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: 90390521 = 13 ⋅6953117.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12509309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12509389) 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, 271919 + ... + 271964.

It is an arithmetic number, because the mean of its divisors is an integer number (3263304).

Almost surely, 2^12509309 is an apocalyptic number.

It is an amenable number.

12509309 is a deficient number, since it is larger than the sum of its proper divisors (543907).

12509309 is an equidigital number, since it uses as much as digits as its factorization.

12509309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 543906.

The product of its (nonzero) digits is 2430, while the sum is 29.

The square root of 12509309 is about 3536.8501523248. The cubic root of 12509309 is about 232.1370387857.

The spelling of 12509309 in words is "twelve million, five hundred nine thousand, three hundred nine".