For example , there are six divisors of 4 ; they are 1 , 2 , 4 , − 1 , − 2 , and − 4 , but only the positive ones ( 1 , 2 , and 4 ) would usually be mentioned .
( For example , there are six divisors of four , 1 , 2 , 4 , -1 , -2 , -4 , but one would usually mention only the positive ones , 1 , 2 , and 4 . )