An integer is classified as any rational number that has no fractional component.
Integers are used when you need a number with no decimal place or it doesn't make sense to have a decimal. Because integers are whole numbers, there are no integers between 1 and 2.
In an IntValue, the lowest value it can hold is -231 or -2,147,483,648. The highest value it can hold is 231-1, or 2,147,483,647. This is a 32-bit (or long) signed integer value.
In Lua, there are no specific integer numbers. The number values are actually double precision floating point (or just 'double') numbers.