A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 5155040 can be evenly divided by 1 2 4 5 8 10 11 16 20 22 29 32 40 44 55 58 80 88 101 110 116 145 160 176 202 220 232 290 319 352 404 440 464 505 580 638 808 880 928 1,010 1,111 1,160 1,276 1,595 1,616 1,760 2,020 2,222 2,320 2,552 2,929 3,190 3,232 4,040 4,444 4,640 5,104 5,555 5,858 6,380 8,080 8,888 10,208 11,110 11,716 12,760 14,645 16,160 17,776 22,220 23,432 25,520 29,290 32,219 35,552 44,440 46,864 51,040 58,580 64,438 88,880 93,728 117,160 128,876 161,095 177,760 234,320 257,752 322,190 468,640 515,504 644,380 1,031,008 1,288,760 2,577,520 and 5,155,040, with no remainder.
Since 5,155,040 cannot be divided by just 1 and 5,155,040, it is not a prime number.