A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 5220540 can be evenly divided by 1 2 3 4 5 6 9 10 12 13 15 18 20 23 26 30 36 39 45 46 52 60 65 69 78 90 92 97 115 117 130 138 156 180 194 195 207 230 234 260 276 291 299 345 388 390 414 460 468 485 582 585 598 690 780 828 873 897 970 1,035 1,164 1,170 1,196 1,261 1,380 1,455 1,495 1,746 1,794 1,940 2,070 2,231 2,340 2,522 2,691 2,910 2,990 3,492 3,588 3,783 4,140 4,365 4,462 4,485 5,044 5,382 5,820 5,980 6,305 6,693 7,566 8,730 8,924 8,970 10,764 11,155 11,349 12,610 13,386 13,455 15,132 17,460 17,940 18,915 20,079 22,310 22,698 25,220 26,772 26,910 29,003 33,465 37,830 40,158 44,620 45,396 53,820 56,745 58,006 66,930 75,660 80,316 87,009 100,395 113,490 116,012 133,860 145,015 174,018 200,790 226,980 261,027 290,030 348,036 401,580 435,045 522,054 580,060 870,090 1,044,108 1,305,135 1,740,180 2,610,270 and 5,220,540, with no remainder.
Since 5,220,540 cannot be divided by just 1 and 5,220,540, it is not a prime number.