A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1414560 can be evenly divided by 1 2 3 4 5 6 7 8 10 12 14 15 16 20 21 24 28 30 32 35 40 42 48 56 60 70 80 84 96 105 112 120 140 160 168 210 224 240 280 336 420 421 480 560 672 840 842 1,120 1,263 1,680 1,684 2,105 2,526 2,947 3,360 3,368 4,210 5,052 5,894 6,315 6,736 8,420 8,841 10,104 11,788 12,630 13,472 14,735 16,840 17,682 20,208 23,576 25,260 29,470 33,680 35,364 40,416 44,205 47,152 50,520 58,940 67,360 70,728 88,410 94,304 101,040 117,880 141,456 176,820 202,080 235,760 282,912 353,640 471,520 707,280 and 1,414,560, with no remainder.
Since 1,414,560 cannot be divided by just 1 and 1,414,560, it is not a prime number.