A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 5180280 can be evenly divided by 1 2 3 4 5 6 7 8 10 12 14 15 20 21 24 28 30 35 40 42 49 56 60 70 84 98 105 120 140 147 168 196 210 245 280 294 392 420 490 588 735 840 881 980 1,176 1,470 1,762 1,960 2,643 2,940 3,524 4,405 5,286 5,880 6,167 7,048 8,810 10,572 12,334 13,215 17,620 18,501 21,144 24,668 26,430 30,835 35,240 37,002 43,169 49,336 52,860 61,670 74,004 86,338 92,505 105,720 123,340 129,507 148,008 172,676 185,010 215,845 246,680 259,014 345,352 370,020 431,690 518,028 647,535 740,040 863,380 1,036,056 1,295,070 1,726,760 2,590,140 and 5,180,280, with no remainder.
Since 5,180,280 cannot be divided by just 1 and 5,180,280, it is not a prime number.