I'm curious why this dumps the reference to @result.

Consider:

22:45 >perl -MData::Dumper -wE "my @c = ( 5, 7, 11 ); say Dumper @c; s
+ay Dumper \@c;"
$VAR1 = 5;
$VAR2 = 7;
$VAR3 = 11;

$VAR1 = [
          5,
          7,
          11
        ];


22:46 >
[download]

I prefer the second form, because I can more easily see the related things grouped together (but YMMV).

my run at the problem resulted in this code:

And now the problem can be diagnosed! It’s in this line:

    my @factors = [ ];
[download]

The square brackets create an empty, anonymous array, and a reference to this anonymous array becomes the first element in the named array @factors. Later, when List::Util::max is called on @factors, it tries to compare the elements in the array to one another, but fails because it doesn’t know how to compare an array reference (that first element) to a Math::BigInt object.

The solution is to simply remove the anonymous array reference, which isn’t needed anyway:

    my @factors;
[download]

and the code now runs without error!

Hope that helps,