12566509 has 2 divisors, whose sum is σ = 12566510. Its totient is φ = 12566508.

The previous prime is 12566473. The next prime is 12566537. The reversal of 12566509 is 90566521.

It is a happy number.

12566509 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11410884 + 1155625 = 3378^2 + 1075^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12566509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12566539) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6283254 + 6283255.

It is an arithmetic number, because the mean of its divisors is an integer number (6283255).

Almost surely, 2^12566509 is an apocalyptic number.

It is an amenable number.

12566509 is a deficient number, since it is larger than the sum of its proper divisors (1).

12566509 is an equidigital number, since it uses as much as digits as its factorization.

12566509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16200, while the sum is 34.

The square root of 12566509 is about 3544.9272206916. The cubic root of 12566509 is about 232.4903237195.

The spelling of 12566509 in words is "twelve million, five hundred sixty-six thousand, five hundred nine".