17. $N$ pieces of candy are made and packed into boxes, with each box containing 45 pieces. If $N$ is a non-zero perfect cube and 45 is one of its factors, what is the least possible number of boxes that can be packed?
17. Ans: 75 .
The least non-zero perfect cube of the form $45 \mathrm{~m}=3^{2} \cdot 5 \mathrm{~m}$ is $3^{3} \times 5^{3}$. Thus the least possible number of boxes that can be packed is $3 \times 5^{2}=75$.