A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 8490020 can be evenly divided by 1 2 4 5 7 10 11 14 20 22 28 35 37 44 55 70 74 77 110 140 148 149 154 185 220 259 298 308 370 385 407 518 596 740 745 770 814 1,036 1,043 1,295 1,490 1,540 1,628 1,639 2,035 2,086 2,590 2,849 2,980 3,278 4,070 4,172 5,180 5,215 5,513 5,698 6,556 8,140 8,195 10,430 11,026 11,396 11,473 14,245 16,390 20,860 22,052 22,946 27,565 28,490 32,780 38,591 45,892 55,130 56,980 57,365 60,643 77,182 110,260 114,730 121,286 154,364 192,955 229,460 242,572 303,215 385,910 424,501 606,430 771,820 849,002 1,212,860 1,698,004 2,122,505 4,245,010 and 8,490,020, with no remainder.
Since 8,490,020 cannot be divided by just 1 and 8,490,020, it is not a prime number.