The LCM of 6, 9, 18, and 27 is 54. Multiples of 6 are 6, 12, 18, 24, 30, 36, 42, 48, 54, and so on Multiples of 9 are 9, 18, 27, 36, 45, 54, and so on. Multiples of 18 are 18, 36, 54, and so on. Multiples of 27 are 27, 54, and so on So the LCM of 6, 9, 18, and 27 is 54.