regex para el número más grande
var myString = "857nano620348splitted3412674relation5305743";
var largest = Math.max.apply(null, myString.match(/\d+/g));
Gifted Gorilla
var myString = "857nano620348splitted3412674relation5305743";
var largest = Math.max.apply(null, myString.match(/\d+/g));