Maybe , this question would better be asked in another forum. If yes, what is the proper one ?
Here
https://factordb.com/index.php?id=1100000000900921624
the factor database seems to have a bug! The number is prime, but it is displayed to be composite.
Does anyone know this site and how to report or remove bugs there ?
Let $n = (10^{39}-451) \text{ mod } {\displaystyle{\frac{10^{39}-1}{9}}}$
$\qquad\; = 111111111111111111111111111111111110661$
Then $2^{n-1} \text{ mod }n$ reduces to
$\qquad\;\;\;\;\;\,\, 78402869353071463352746795182243243082$
hence, by Fermat's little Theorem, $n$ is not prime.
So, the "bug" is probably just a typo in how they showed the base-10 expansion of $n$.