They are infinite, starting with these: 684, 1368, 2052, 2736 +684 . . .
684, 1368, 2052, 2736, 3420
228, 456, 684, 912, 1140 . . .
All of its multiples are. There are an infinite number of them.
228, 456, 684 and so on.
342, 684, 1026, 1368, 1710, 2052, 2394, . . .
228, 456, 684
57, 114, 171, 228, 285, 342, 399, 456, 513, 570, 627, 684, . . .
76, 152, 228, 304, 380, 456, 532, 608, 684, 760.
4 is not divisible by 684. 684 is divisible by 4.
684 ÷ 2 = 342
The difference is 1070 minus 684 = 386
No. 684 is a composite number.