A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 8538300 can be evenly divided by 1 2 3 4 5 6 9 10 12 15 18 20 25 30 36 45 50 53 60 75 90 100 106 150 159 179 180 212 225 265 300 318 358 450 477 530 537 636 716 795 895 900 954 1,060 1,074 1,325 1,590 1,611 1,790 1,908 2,148 2,385 2,650 2,685 3,180 3,222 3,580 3,975 4,475 4,770 5,300 5,370 6,444 7,950 8,055 8,950 9,487 9,540 10,740 11,925 13,425 15,900 16,110 17,900 18,974 23,850 26,850 28,461 32,220 37,948 40,275 47,435 47,700 53,700 56,922 80,550 85,383 94,870 113,844 142,305 161,100 170,766 189,740 237,175 284,610 341,532 426,915 474,350 569,220 711,525 853,830 948,700 1,423,050 1,707,660 2,134,575 2,846,100 4,269,150 and 8,538,300, with no remainder.
Since 8,538,300 cannot be divided by just 1 and 8,538,300, it is not a prime number.