A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1687200 can be evenly divided by 1 2 3 4 5 6 8 10 12 15 16 19 20 24 25 30 32 37 38 40 48 50 57 60 74 75 76 80 95 96 100 111 114 120 148 150 152 160 185 190 200 222 228 240 285 296 300 304 370 380 400 444 456 475 480 555 570 592 600 608 703 740 760 800 888 912 925 950 1,110 1,140 1,184 1,200 1,406 1,425 1,480 1,520 1,776 1,824 1,850 1,900 2,109 2,220 2,280 2,400 2,775 2,812 2,850 2,960 3,040 3,515 3,552 3,700 3,800 4,218 4,440 4,560 5,550 5,624 5,700 5,920 7,030 7,400 7,600 8,436 8,880 9,120 10,545 11,100 11,248 11,400 14,060 14,800 15,200 16,872 17,575 17,760 21,090 22,200 22,496 22,800 28,120 29,600 33,744 35,150 42,180 44,400 45,600 52,725 56,240 67,488 70,300 84,360 88,800 105,450 112,480 140,600 168,720 210,900 281,200 337,440 421,800 562,400 843,600 and 1,687,200, with no remainder.
Since 1,687,200 cannot be divided by just 1 and 1,687,200, it is not a prime number.