7 can go into 21 , 3 times
1, 3, 7, 21.
21
21
anonymos is correct
It is: 21
They are infinite, starting with these: 684, 1368, 2052, 2736 +684 . . .
4 is not divisible by 684. 684 is divisible by 4.
Because 3 divides evenly into 21 and 36 with no remainder.
3
1 and 7.
If 21 divides into M then all the factors of 21 must divide into M.The factors of 21 are 1, 3, 7, 21 (we usually avoid the factor 1 and the number)So, 3 and 7 must divide into M.