A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 5118300 can be evenly divided by 1 2 3 4 5 6 9 10 11 12 15 18 20 22 25 30 33 36 44 45 47 50 55 60 66 75 90 94 99 100 110 121 132 141 150 165 180 188 198 220 225 235 242 275 282 300 330 363 396 423 450 470 484 495 517 550 564 605 660 705 726 825 846 900 940 990 1,034 1,089 1,100 1,175 1,210 1,410 1,452 1,551 1,650 1,692 1,815 1,980 2,068 2,115 2,178 2,350 2,420 2,475 2,585 2,820 3,025 3,102 3,300 3,525 3,630 4,230 4,356 4,653 4,700 4,950 5,170 5,445 5,687 6,050 6,204 7,050 7,260 7,755 8,460 9,075 9,306 9,900 10,340 10,575 10,890 11,374 12,100 12,925 14,100 15,510 17,061 18,150 18,612 21,150 21,780 22,748 23,265 25,850 27,225 28,435 31,020 34,122 36,300 38,775 42,300 46,530 51,183 51,700 54,450 56,870 68,244 77,550 85,305 93,060 102,366 108,900 113,740 116,325 142,175 155,100 170,610 204,732 232,650 255,915 284,350 341,220 426,525 465,300 511,830 568,700 853,050 1,023,660 1,279,575 1,706,100 2,559,150 and 5,118,300, with no remainder.
Since 5,118,300 cannot be divided by just 1 and 5,118,300, it is not a prime number.