12506809 has 10 divisors (see below), whose sum is σ = 14593210. Its totient is φ = 10718064.

The previous prime is 12506783. The next prime is 12506821. The reversal of 12506809 is 90860521.

It can be written as a sum of positive squares in only one way, i.e., 12446784 + 60025 = 3528^2 + 245^2 .

It is not a de Polignac number, because 12506809 - 2¹⁵ = 12474041 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12506869) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 204 + ... + 5005.

It is an arithmetic number, because the mean of its divisors is an integer number (1459321).

Almost surely, 2^12506809 is an apocalyptic number.

It is an amenable number.

12506809 is a deficient number, since it is larger than the sum of its proper divisors (2086401).

12506809 is an frugal number, since it uses more digits than its factorization.

12506809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5237 (or 5216 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 12506809 is about 3536.4967128502. The cubic root of 12506809 is about 232.1215734694.

The spelling of 12506809 in words is "twelve million, five hundred six thousand, eight hundred nine".