A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3840540 can be evenly divided by 1 2 3 4 5 6 10 11 12 15 20 22 23 30 33 44 46 55 60 66 69 92 110 115 121 132 138 165 220 230 242 253 276 330 345 363 460 484 506 529 605 660 690 726 759 1,012 1,058 1,210 1,265 1,380 1,452 1,518 1,587 1,815 2,116 2,420 2,530 2,645 2,783 3,036 3,174 3,630 3,795 5,060 5,290 5,566 5,819 6,348 7,260 7,590 7,935 8,349 10,580 11,132 11,638 13,915 15,180 15,870 16,698 17,457 23,276 27,830 29,095 31,740 33,396 34,914 41,745 55,660 58,190 64,009 69,828 83,490 87,285 116,380 128,018 166,980 174,570 192,027 256,036 320,045 349,140 384,054 640,090 768,108 960,135 1,280,180 1,920,270 and 3,840,540, with no remainder.
Since 3,840,540 cannot be divided by just 1 and 3,840,540, it is not a prime number.