Number

The number type is inhabited by real numeric values. Specifically, it has 53 bits of precision, meaning it can accurately represent integral values in the interval $$\left[-2^{53},2^{53}\right]$$, outside of which arithmetic operations will gradually lose precision. This is because the number type is implemented using double-precision floating-point numbers.

NaN
NaN, which stands for not a number, is a special value of the number type. In Lua, it is the only value that is not equal to itself.