Nodejs Utililty Methods Number Check

(function(){
"use strict";
Number.prototype.isInRange = function isInRange(lower, upper){
  if (this >= lower && this <= upper){
    return true;
  if (this <= lower && this >= upper){
    return true;
  return false;
};

Number.prototype.isMultipleof = function (num) {
  if (this % num === 0) {
    return true;
  return false;
var result = 0;
for (var i = 1; i < 1000; i++) {
  if (i.isMultipleof(3) || i.isMultipleof(5) ) {
...

Number.prototype.isNegativeZero = function() {
  var n = this;
  return n === 0 && (((n = +n) || (1 / n)) < 0);

Number.prototype.isPalindrome = function() {
  return this == this.reverse();
var max = 0
  , x;
for (var i = 100; i < 999; i++) {
  for (var j = i; j < 999; j++) {
    x = i * j;
    if (x.isPalindrome() && x > max) {
...

Number.prototype.isPerfPow = function(nroot){
  var primes = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53];
  var root,log2,t;
  t = Math.abs(this);
  log2 = Math.floor(Math.log(t)/Math.LN2);
  if(this.isPow2()) return true;
  root = Math.round(Math.sqrt(t));
  if(t - (root * root) == 0){
    if(arguments.length  > 0){
...

Number.prototype.isPositive = function() {
  return this > 0;

Number.prototype.isPositive = function(){
  return this > 0;
var numb = new Number(10);
console.log(numb.isPositive());