title: How do I add "123" to the beginning of a string and pad it to be exactly 12 chars?
body: <p>I need to add &quot;123&quot; and zeros for any string - but the resulting string must be exactly 12 characters long.</p>
  <p>For example:</p>
  <pre><code>28431 = 123000028431
  987   = 123000000987
  2     = 123000000002
  </code></pre>
  <p>How to do this in C#?</p>