Derek’s phone number, 336-7624, has the property that the three-digit prefix, 336, equals the product of the last four digits, 7 × 6 × 2 × 4. How many seven-digit phone numbers beginning with 336 have this property?
1678 1687 1768 1786 1867 1876 2378 2387 2467 2476 2647 2674 2738 2746 2764 2783 2837 2873 3278 3287 3447 3474 3728 3744 3782 3827 3872 4267 4276 4347 4374 4437 4473 4627 4672 4726 4734 4743 4762 6178 6187 6247 6274 6427 6472 6718 6724 6742 6781 6817 6871 7168 7186 7238 7246 7264 7283 7328 7344 7382 7426 7434 7443 7462 7618 7624 7642 7681 7816 7823 7832 7861 8167 8176 8237 8273 8327 8372 8617 8671 8716 8723 8732 8761 Total = 84 such numbers.
