numbers that are not 0 to 2 , 4, 8 or the only factor they have is 2, meaning that it is not 4,8,16,32,64,128,256,512,1024,2048,4096,8192.....so on and so forth but you get the idea,right? it is definitely not squared numbers 2 square is 4 but has no odd number for factors at all same goes for any other number with the base power of 2