A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 5388780 can be evenly divided by 1 2 3 4 5 6 10 12 15 19 20 29 30 38 57 58 60 76 87 95 114 116 145 163 174 190 228 285 290 326 348 380 435 489 551 570 580 652 815 870 978 1,102 1,140 1,630 1,653 1,740 1,956 2,204 2,445 2,755 3,097 3,260 3,306 4,727 4,890 5,510 6,194 6,612 8,265 9,291 9,454 9,780 11,020 12,388 14,181 15,485 16,530 18,582 18,908 23,635 28,362 30,970 33,060 37,164 46,455 47,270 56,724 61,940 70,905 89,813 92,910 94,540 141,810 179,626 185,820 269,439 283,620 359,252 449,065 538,878 898,130 1,077,756 1,347,195 1,796,260 2,694,390 and 5,388,780, with no remainder.
Since 5,388,780 cannot be divided by just 1 and 5,388,780, it is not a prime number.