Number - NaN (Not A Number)

About

NaN, or Not a Number, is a value that returns when impossible things are asked in arithmetic – like:

• divide zero by zero.
• or during the bad coercion

NaN (paradoxically named not a number) is a special floating-point value in the IEEE floating-point standard.

Articles Related

Management

Not equal to itself

The IEEE floating-point standard requires that NaN must be treated as unequal to itself.

Demo in Javascript:

console.log(NaN === NaN);    // false