16 has several factors, BUT bear in mind that 17 is a prime number, it has no factors other 1, so 16/17 cannot be simplified,
[tex]\bf \cfrac{16}{17}\qquad \cfrac{8}{32}\implies \cfrac{16}{17}\qquad \cfrac{1}{4}\implies \cfrac{16}{17}~\ne~ \cfrac{1}{4}[/tex]
