12638909 has 2 divisors, whose sum is σ = 12638910. Its totient is φ = 12638908.

The previous prime is 12638903. The next prime is 12638953. The reversal of 12638909 is 90983621.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11868025 + 770884 = 3445^2 + 878^2 .

It is an emirp because it is prime and its reverse (90983621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12638909 - 2⁴ = 12638893 is a prime.

It is a Chen prime.

It is a plaindrome in base 15.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12638903) 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 as a sum of consecutive naturals, namely, 6319454 + 6319455.

It is an arithmetic number, because the mean of its divisors is an integer number (6319455).

Almost surely, 2^12638909 is an apocalyptic number.

It is an amenable number.

12638909 is a deficient number, since it is larger than the sum of its proper divisors (1).

12638909 is an equidigital number, since it uses as much as digits as its factorization.

12638909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 12638909 is about 3555.1243297528. The cubic root of 12638909 is about 232.9359546937.

The spelling of 12638909 in words is "twelve million, six hundred thirty-eight thousand, nine hundred nine".