See, 6 is three times the number 2. And 24 is four times the number 6. 120 is 5 times the number 24.

The pattern is such that the next number is x times the previous number (where x is equal to (1+ previous multiplication factor). For ex., 6/2 = 3 so the next number will be (3+1) = 4 times the number 6).

Hence the next number in the sequence will be 120*6 = 720.