A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3502980 can be evenly divided by 1 2 3 4 5 6 9 10 12 13 15 18 20 26 27 30 36 39 45 52 54 60 65 78 90 108 117 130 135 156 180 195 234 260 270 351 390 468 499 540 585 702 780 998 1,170 1,404 1,497 1,755 1,996 2,340 2,495 2,994 3,510 4,491 4,990 5,988 6,487 7,020 7,485 8,982 9,980 12,974 13,473 14,970 17,964 19,461 22,455 25,948 26,946 29,940 32,435 38,922 44,910 53,892 58,383 64,870 67,365 77,844 89,820 97,305 116,766 129,740 134,730 175,149 194,610 233,532 269,460 291,915 350,298 389,220 583,830 700,596 875,745 1,167,660 1,751,490 and 3,502,980, with no remainder.
Since 3,502,980 cannot be divided by just 1 and 3,502,980, it is not a prime number.