A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 5115300 can be evenly divided by 1 2 3 4 5 6 10 12 15 17 20 25 30 34 50 51 59 60 68 75 85 100 102 118 150 170 177 204 236 255 289 295 300 340 354 425 510 578 590 708 850 867 885 1,003 1,020 1,156 1,180 1,275 1,445 1,475 1,700 1,734 1,770 2,006 2,550 2,890 2,950 3,009 3,468 3,540 4,012 4,335 4,425 5,015 5,100 5,780 5,900 6,018 7,225 8,670 8,850 10,030 12,036 14,450 15,045 17,051 17,340 17,700 20,060 21,675 25,075 28,900 30,090 34,102 43,350 50,150 51,153 60,180 68,204 75,225 85,255 86,700 100,300 102,306 150,450 170,510 204,612 255,765 300,900 341,020 426,275 511,530 852,550 1,023,060 1,278,825 1,705,100 2,557,650 and 5,115,300, with no remainder.
Since 5,115,300 cannot be divided by just 1 and 5,115,300, it is not a prime number.