A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3361260 can be evenly divided by 1 2 3 4 5 6 7 10 12 14 15 20 21 28 30 35 42 53 60 70 84 105 106 140 151 159 210 212 265 302 318 371 420 453 530 604 636 742 755 795 906 1,057 1,060 1,113 1,484 1,510 1,590 1,812 1,855 2,114 2,226 2,265 3,020 3,171 3,180 3,710 4,228 4,452 4,530 5,285 5,565 6,342 7,420 8,003 9,060 10,570 11,130 12,684 15,855 16,006 21,140 22,260 24,009 31,710 32,012 40,015 48,018 56,021 63,420 80,030 96,036 112,042 120,045 160,060 168,063 224,084 240,090 280,105 336,126 480,180 560,210 672,252 840,315 1,120,420 1,680,630 and 3,361,260, with no remainder.
Since 3,361,260 cannot be divided by just 1 and 3,361,260, it is not a prime number.