title: Generate an N-digit random number
body: <p>I want to generate a 6 digit random number using the PHP <code>mt_rand()</code> function.</p>
  
  <p>I know the PHP <code>mt_rand()</code> function only takes 2 parameters: a <em>minimum</em> and a <em>maximum</em> value.</p>
  
  <p>How can I do that?</p>