Stop function random number

i want stop this function with a button, what can i do for that working ?

Thanks

var module = angular.module('numberApp', []);

module.controller('NumberController', function($scope, $timeout) {
    (function update() {
    $timeout(update, 1000 * 15);
    $scope.randomNumber = Math.floor(Math.random()*($scope.max-$scope.min+1)+$scope.min);
  }());

please help me to stop this function with a button ;-)