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.

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