number

数(かず)	Number as in “200 years ago” or “43 people showed up.” $$$

数字(すうじ)	An integer – 1,2,3 are 数字 the same way that a,b, and c are 文字. (Or あ、い、え、う、お　for that matter!)

号(ごう)	A number which has been assigned to an object, as in, ‘room number’ or ‘phone number.’