One way to do it, similar to talexb, would be (tested!) 
use Math::Big::Factors;

my $val = 2000;

my @x = Math::Big::Factors::factors_wheel( $val );
print "@x\n";

my %factors;
$factors{$_}++ for @x;

use Data::Dumper;
print Dumper \%factors;

my $sqrt = 1;
while (my ($k,$v) = each %factors) {
    while ($v > 1) {
        $sqrt *= $k;
        $v -= 2;
    }

    if ($v) {
         $sqrt *= sqrt( $k );
    }
}

print "$sqrt => ", sqrt( $val ), $/;

[download]
This is going to be slower that just taking the sqrt of the value. Just to let you know ...

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Being unknowing, is not the same as being stupid.
Expressing a contrary opinion, whether to the individual or the group, is more often a sign of deeper thought than of cantankerous belligerence.
Do not mistake your goals as the only goals; your opinion as the only opinion; your confidence as correctness. Saying you know better is not the same as explaining you know better.

In reply to Re^3: OT: Finding Factor Closest To Square Root by dragonchild
in thread OT: Finding Factor Closest To Square Root by QM

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