A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3874500 can be evenly divided by 1 2 3 4 5 6 7 9 10 12 14 15 18 20 21 25 27 28 30 35 36 41 42 45 50 54 60 63 70 75 82 84 90 100 105 108 123 125 126 135 140 150 164 175 180 189 205 210 225 246 250 252 270 287 300 315 350 369 375 378 410 420 450 492 500 525 540 574 615 630 675 700 738 750 756 820 861 875 900 945 1,025 1,050 1,107 1,125 1,148 1,230 1,260 1,350 1,435 1,476 1,500 1,575 1,722 1,750 1,845 1,890 2,050 2,100 2,214 2,250 2,460 2,583 2,625 2,700 2,870 3,075 3,150 3,375 3,444 3,500 3,690 3,780 4,100 4,305 4,428 4,500 4,725 5,125 5,166 5,250 5,535 5,740 6,150 6,300 6,750 7,175 7,380 7,749 7,875 8,610 9,225 9,450 10,250 10,332 10,500 11,070 12,300 12,915 13,500 14,350 15,375 15,498 15,750 17,220 18,450 18,900 20,500 21,525 22,140 23,625 25,830 27,675 28,700 30,750 30,996 31,500 35,875 36,900 38,745 43,050 46,125 47,250 51,660 55,350 61,500 64,575 71,750 77,490 86,100 92,250 94,500 107,625 110,700 129,150 138,375 143,500 154,980 184,500 193,725 215,250 258,300 276,750 322,875 387,450 430,500 553,500 645,750 774,900 968,625 1,291,500 1,937,250 and 3,874,500, with no remainder.
Since 3,874,500 cannot be divided by just 1 and 3,874,500, it is not a prime number.