There are really only three distinct factor pairs:
(16, 1) (8, 2)
(4, 4)
I suppose if you count (1,16) and (2,8) as being different from (16, 1) and (8,2), you could end up with as many as five factor pairs.
Factor pairs of 16 are 1 and 16, 2 and 8, and 4 and 4.
2&8 4&4 16&1
1 and 16 2 and 8 4 and 4
1 and 16,2 and 8, 4 and 4
16 = 1 x 16 16 = 2 x 8 16 = 4 x 4
The factor pairs of 16 are 1x16, 8x2, and 4x4
The factor pairs of 112 are 1*112, 2*56, 4*28, 7*16, and 8*14
1 x 16 2 x 8 4 x 4
(16,1)(8,2)(4,4)
The factor pairs of 16 are (16,1)(8,2)(4,4)
There are 5 factor pairs of 256.256 = 1 x 256256 = 2 x 128256 = 4 x 64256 = 8 x 32256 = 16 x 16
These are the 16 factor pairs for the number 1,080:1080,1540,2360,3270,4216,5180,6135,8120,9108,1090,1272,1560,1854,2045,2440,2736,30