A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 4145850 can be evenly divided by 1 2 3 5 6 9 10 15 18 25 27 30 37 45 50 54 74 75 83 90 111 135 150 166 185 222 225 249 270 333 370 415 450 498 555 666 675 747 830 925 999 1,110 1,245 1,350 1,494 1,665 1,850 1,998 2,075 2,241 2,490 2,775 3,071 3,330 3,735 4,150 4,482 4,995 5,550 6,142 6,225 7,470 8,325 9,213 9,990 11,205 12,450 15,355 16,650 18,426 18,675 22,410 24,975 27,639 30,710 37,350 46,065 49,950 55,278 56,025 76,775 82,917 92,130 112,050 138,195 153,550 165,834 230,325 276,390 414,585 460,650 690,975 829,170 1,381,950 2,072,925 and 4,145,850, with no remainder.
Since 4,145,850 cannot be divided by just 1 and 4,145,850, it is not a prime number.