A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3745500 can be evenly divided by 1 2 3 4 5 6 10 11 12 15 20 22 25 30 33 44 50 55 60 66 75 100 110 125 132 150 165 220 227 250 275 300 330 375 454 500 550 660 681 750 825 908 1,100 1,135 1,362 1,375 1,500 1,650 2,270 2,497 2,724 2,750 3,300 3,405 4,125 4,540 4,994 5,500 5,675 6,810 7,491 8,250 9,988 11,350 12,485 13,620 14,982 16,500 17,025 22,700 24,970 28,375 29,964 34,050 37,455 49,940 56,750 62,425 68,100 74,910 85,125 113,500 124,850 149,820 170,250 187,275 249,700 312,125 340,500 374,550 624,250 749,100 936,375 1,248,500 1,872,750 and 3,745,500, with no remainder.
Since 3,745,500 cannot be divided by just 1 and 3,745,500, it is not a prime number.