title: Check if last X characters of a field are numeric
body: <p>In fact there are 2 questions, 2 queries:</p>
  
  <ul>
  <li>I'd need to find out is a numeric that beginning with <code>'541'</code> is <code>18 chars</code> long
  In fact there is a space right after SO: <code>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when....'541'....15RandomNumbers in (0,1,2,3,4,5,6,7,8,9).....an unknown printer took a galley of type and scrambled it to make a type specimen book.</code></li>
  <li>Second: Check if last 18 chars of a string are numeric (maybe after a trim right)</li>
  </ul>
  
  <p>That's it,</p>