while ( $vlnum > 0 ) {
    $vldig = $vlnum % 10; 
    $vlsum = $vlsum + ($vldig * $vldig * $vldig);
    $vlnum = $vlnum / 10;
}

##</code><code>##

#!/usr/bin/perl -w

use strict;

my $vlnum = 0;
my $vlsum = 0;

print "Insert a number: ";
chomp ( $vlnum = <STDIN> );

# map { $vlsum += $_ ** 3 } split //, $vlnum;
# oops, this should be (thanks [broquaint]!):

$vlsum += $_ ** 3 for split //, $vlnum;

if ( $vlsum == $vlnum ) { 
    print "Is narc dude!"; 
} else { 
    print "Try another number!"; 
}