Chapter 8.1, Problem 2P

Manuela is looking for all the factors of 90. So far, she has divided 90 by all the counting numbers from 1 to 10, listing those numbers that divide 90 and listing the corresponding quotients. Here is Manuela’s work so far:

$\begin{array}{l}1,901\times 90=90\hfill \\ 2,452\times 45=90\hfill \\ 3,303\times 30=90\hfill \\ 5,185\times 18=90\hfill \\ 6,156\times 15=90\hfill \\ 9,109\times 10=90\hfill \\ 10,910\times 9=90\hfill \end{array}$

Should Manuela keep checking numbers to see if any numbers larger than 10 divide 90, or can Manuela stop dividing at this point? If so, why? What are all the factors of 90?