A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3608280 can be evenly divided by 1 2 3 4 5 6 8 9 10 12 13 15 18 20 24 26 27 30 36 39 40 45 52 54 60 65 72 78 90 104 108 117 120 130 135 156 180 195 216 234 257 260 270 312 351 360 390 468 514 520 540 585 702 771 780 936 1,028 1,080 1,170 1,285 1,404 1,542 1,560 1,755 2,056 2,313 2,340 2,570 2,808 3,084 3,341 3,510 3,855 4,626 4,680 5,140 6,168 6,682 6,939 7,020 7,710 9,252 10,023 10,280 11,565 13,364 13,878 14,040 15,420 16,705 18,504 20,046 23,130 26,728 27,756 30,069 30,840 33,410 34,695 40,092 46,260 50,115 55,512 60,138 66,820 69,390 80,184 90,207 92,520 100,230 120,276 133,640 138,780 150,345 180,414 200,460 240,552 277,560 300,690 360,828 400,920 451,035 601,380 721,656 902,070 1,202,760 1,804,140 and 3,608,280, with no remainder.
Since 3,608,280 cannot be divided by just 1 and 3,608,280, it is not a prime number.