12539809 has 4 divisors (see below), whose sum is σ = 12845700. Its totient is φ = 12233920.

The previous prime is 12539797. The next prime is 12539819. The reversal of 12539809 is 90893521.

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 1149184 + 11390625 = 1072^2 + 3375^2 .

It is a cyclic number.

It is not a de Polignac number, because 12539809 - 2⁵ = 12539777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12539819) 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, 152884 + ... + 152965.

It is an arithmetic number, because the mean of its divisors is an integer number (3211425).

Almost surely, 2^12539809 is an apocalyptic number.

It is an amenable number.

12539809 is a deficient number, since it is larger than the sum of its proper divisors (305891).

12539809 is an equidigital number, since it uses as much as digits as its factorization.

12539809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 305890.

The product of its (nonzero) digits is 19440, while the sum is 37.

The square root of 12539809 is about 3541.1592734583. The cubic root of 12539809 is about 232.3255499498.

The spelling of 12539809 in words is "twelve million, five hundred thirty-nine thousand, eight hundred nine".