Show if the following PHP code returns TRUE (PHP-mode, experts only)

Hi,

I would like to hide a block if the NID is equal to 616565, the following code I have used doesn’t seem to work?!

<?php 
if($node->nid == ‘616565’){
return false;
}
?>

Drupal version: 


Source: https://www.drupal.org/taxonomy/term/4/feed