Final answer:
The number 0.8394756 is a rational number as it can be expressed as a fraction of two integers and does not fit the definition of irrational numbers, natural numbers, integers, or whole numbers.
Step-by-step explanation:
The number 0.8394756 is a rational number because it can be expressed as a fraction of two integers. A decimal which terminates or has a repeating pattern after a certain point is considered rational. It is not an irrational number because irrational numbers cannot be expressed as a simple fraction.
It is also not a natural number, an integer, or a whole number because those sets only include positive whole numbers, (natural includes all positive integers, whole includes zero), and integers include negative numbers as well as whole numbers.