All numbers in the physical world are (positive) real numbers.
Real numbers are all numbers from minus infinity to plus infinity.
Integers are real (rational) numbers with a fractional (decimal part) value of zero or, with no fractional or decimal part.
Real numbers are divided in to rational numbers and irrational numbers.
Irrational numbers cannot be expressed as a ratio of p / q, where p and q are integers.
Rational numbers are further divided in to fractions and whole numbers or integers.
Examples of integers are -21324, -4 , 0 , +1, +838383