no numbers!
Nothing can go evenly into 21 or 17. They are both odd numbers and therefore cannot be evenly divided.
The numbers that go into 30 are1, 2, 3, 5, 30, 15, 10, 6
60.5
1,2,3,6,7
11,6,1,2,33
n
2,4,7
1,2,4,8,16,32
1,3,5,9,15,45
255
These whole numbers go evenly into 64: 1, 2, 4, 8, 16, 32, 64.