Hey Paul,
Please try the below code for your requirement :
<script type="text/javascript">
$(document).ready(function(){
$('.numeric_input').live("cut copy paste",function(e) {
e.preventDefault();
});
});
$(".numeric_input").on("contextmenu",function(e){
return false; /*right click disable*/
});
</script>
The above code will function for disabling the copy paste and also i have provided the right click disabling which can avoid pasting through mouse clicks
Place the above in footer and based on the question please the class, as now i have provided the code for "numeric_input"