The lowest common multiple of 3, 5, and 7 is 105, so
that's the smallest number that has those prime factors.
Every multiple of 105 is another one:
210, 315, 420, etc.
So is (105) times (any multiple of 3 or 5 or 7):
(x 3, 6, 9) 315, 630, 945, etc.
(x 5, 10, 15) 525, 1050, 1575, etc.
(x 7, 14, 21) 735, 1470, 2205, etc.
