ocr: Factors THE FACTORS ofa number are allt the numbers that can be dividedinto it exactly. THE NUMBER 20 has factors of1,2,4,5, 10,and20. The number 5 has factors of1 1and 5. The numbers 20 and5 theretore share the common factors of1 and5. Any number that can be divided only by itself - and1 is calleda prime number.