Ответ:756 = 2 * 378 = 2 * 2 * 189 = 2 * 2 * 3 * 63 = 2 * 2 * 3 * 3 * 21 = 2 * 2 * 3 * 3 * 3 * 7 = 2^2 * 3^3 * 7.