Answer :

I would say 1 but I feel like that wouldn't help you and that's all I know, plus I don't want to look it up because of the policy. I wanna help tho, so that's all I'm gonna say (please don't get mad at me)
28 - 7x4, 2x14, 4x7, 14x2
21 - 7x3
60 - 2x30, 3x20, 5x12, 6x10, 12x5, 20x3, 30x2
48 - 2x24, 3x16, 4x12, 6x8, 8x6, 12x4, 16x3, 24x2
24 - 2x12, 3x8, 4x6, 6x4, 8x3, 12x2
45 - 3x15, 5x9, 9x5, 15x3