Concepts - Not a Number (NaN)
Not a Number (NaN)
Not a Number (NaN) is a special value returned as the result of math operations that are logically or mathematically invalid.
One of the more common ways to create a NaN value is to divide zero by zero.
Example
NaN has some qualities that may not be immediately obvious, but are important to know:
Additional Info
The NaN value originates from the Floating-Point Number (float) standard used almost universally by software and hardware for non-integer numbers.