What is the greatest common factor between 21 and 27 July 8, 2019 16 32 64 128 What is the greatest common factor of 12 21 and 27 What is the greatest common factor 21 and 27 What is the greatest common factor of 21 27 and 51 What is the greatest common factor of 21 24 and 27 What is the greatest common factor of 2712 and 21