Thanks for the welcome, Athanasius. I like what you did with the number separators (600_851_475_143).

#print Dumper \@result;

I'm curious why this dumps the reference to @result. Is there an advantage to this way of doing it?

Lastly, my run at the problem resulted in this code:

use Modern::Perl '2012';
# "All operators (including basic math operations) are overloaded.
use bigint lib => 'Calc, GMP';
use Regexp::Common;
use Data::Dumper;
use List::Util qw/ max /;
use Carp qw/ confess /;

$SIG{__DIE__} = sub {
    confess @_;
}; 

sub big_factors {
    my $n = shift;
    my @factors = [ ];
    my $d = 2;

    # ensure $n is an integer
    if ($n !~ /$RE{num}{real}/) {
        die "Argument was not a real number.";
    }

    while ($n > 1) {
        while ( 0 == $n % $d) {
            push @factors, $d;
            $n /= $d;
        }

        $d += 1;

        if ($d**2 > $n) {
            if ($n > 1) {
                push @factors, $n;
                last;
            }
        }
    }

    return @factors;
}

my @result = big_factors(600851475143);

say max @result;

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In reply to Re^2: List::Util can't find max in array of BigInts by mgatto
in thread List::Utils can't find max in array of BigInts by mgatto

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