in general, we say that "m" divides "n" for non-zero integers "m" and "n", if and only if there exists an integer "k" such that "n" = "km". thus, divisors can be negative as well as positive, although we often restrict our attention to positive divisors. (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.)