A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1637100 can be evenly divided by 1 2 3 4 5 6 9 10 12 15 17 18 20 25 30 34 36 45 50 51 60 68 75 85 90 100 102 107 150 153 170 180 204 214 225 255 300 306 321 340 425 428 450 510 535 612 642 765 850 900 963 1,020 1,070 1,275 1,284 1,530 1,605 1,700 1,819 1,926 2,140 2,550 2,675 3,060 3,210 3,638 3,825 3,852 4,815 5,100 5,350 5,457 6,420 7,276 7,650 8,025 9,095 9,630 10,700 10,914 15,300 16,050 16,371 18,190 19,260 21,828 24,075 27,285 32,100 32,742 36,380 45,475 48,150 54,570 65,484 81,855 90,950 96,300 109,140 136,425 163,710 181,900 272,850 327,420 409,275 545,700 818,550 and 1,637,100, with no remainder.
Since 1,637,100 cannot be divided by just 1 and 1,637,100, it is not a prime number.