12399209 has 4 divisors (see below), whose sum is σ = 12450900. Its totient is φ = 12347520.

The previous prime is 12399199. The next prime is 12399251. The reversal of 12399209 is 90299321.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6615184 + 5784025 = 2572^2 + 2405^2 .

It is a cyclic number.

It is not a de Polignac number, because 12399209 - 2⁴ = 12399193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12399109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25484 + ... + 25965.

It is an arithmetic number, because the mean of its divisors is an integer number (3112725).

Almost surely, 2^12399209 is an apocalyptic number.

It is an amenable number.

12399209 is a deficient number, since it is larger than the sum of its proper divisors (51691).

12399209 is an equidigital number, since it uses as much as digits as its factorization.

12399209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51690.

The product of its (nonzero) digits is 8748, while the sum is 35.

The square root of 12399209 is about 3521.2510560879. The cubic root of 12399209 is about 231.4539837352.

The spelling of 12399209 in words is "twelve million, three hundred ninety-nine thousand, two hundred nine".