<?php
$string = "One001Two111Three";
$result = preg_replace('/^(.*?\d+)(.*?\d+)(.*?)$/im', '$3/$2/$1', $string ); echo $result;
PD9waHAKCiRzdHJpbmcgPSAiT25lMDAxVHdvMTExVGhyZWUiOwokcmVzdWx0ID0gcHJlZ19yZXBsYWNlKCcvXiguKj9cZCspKC4qP1xkKykoLio/KSQvaW0nLCAnJDMvJDIvJDEnLCAkc3RyaW5nICk7CmVjaG8gJHJlc3VsdDs=