What is the difference between a number and a number object?

Question

What is the difference between a number stored in a normal variable:

var foo = 5; 

And a number object:

var bar = new Number(5);

What can I use a number object for?

Answer 1

A Number object contains some useful methods and properties such as:

Number Object Methods

Method                       Description
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
toExponential(x)    Converts a number into an exponential notation
toFixed(x)          Formats a number with x numbers of digits after the decimal point
toPrecision(x)      Formats a number to x length
toString()          Converts a Number object to a string
valueOf()           Returns the primitive value of a Number object

Number Object Properties

Property                        Description
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
constructor         Returns the function that created the Number object's prototype
MAX_VALUE       Returns the largest number possible in JavaScript
MIN_VALUE           Returns the smallest number possible in JavaScript
NEGATIVE_INFINITY   Represents negative infinity (returned on overflow)
NaN             Represents a "Not-a-Number" value
POSITIVE_INFINITY   Represents infinity (returned on overflow)
prototype           Allows you to add properties and methods to an object

Answer 2

I think in practice there is no difference between this two. All available methods for number objects is also available for primitive numbers. When you invoke a method on a primitive number, the number temporarily gets converted to an object and then the method executes. See the following examples:

var temp1 = Object(1) // number object   
var temp2 = 1         // primitive number

console.log(temp1.toString()) // invoke its own method. result: 1
console.log(temp2.toString()) // temporarily converts to object and invoke number object method. result:1

console.log(Object(1).constructor === Number) //true
console.log((1).constructor === Number)       //true
//             ^---------- temporarily converts to object