title: Calculate 100 factorial with all the digits
body: <p>I came across a problem of calculating <em>100 factorial</em>.</p>
  
  <p>Here is what I tried first in <em>Perl</em> to calculate <strong>100!</strong> :</p>
  
  <pre><code>#!/usr/bin/perl
  
  use strict;
  use warnings;
  use Math::BigInt;
  
  my $n=&lt;&gt;;
  chomp($n);
  print fac($n);
  
  sub fac
  {
      my ($m) = @_;
  
      return 1 if($m &lt;=1 );
      return $m*fac($m-1);
  }
  </code></pre>
  
  <p>But this is giving me <code>9.33262154439441e+157</code>.</p>
  
  <p>I need the answer with all of the digits.</p>
  
  <p>What do I do?</p>