A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1908480 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 64 70 71 80 84 96 105 112 120 128 140 142 160 168 192 210 213 224 240 256 280 284 320 336 355 384 420 426 448 480 497 560 568 640 672 710 768 840 852 896 960 994 1,065 1,120 1,136 1,280 1,344 1,420 1,491 1,680 1,704 1,792 1,920 1,988 2,130 2,240 2,272 2,485 2,688 2,840 2,982 3,360 3,408 3,840 3,976 4,260 4,480 4,544 4,970 5,376 5,680 5,964 6,720 6,816 7,455 7,952 8,520 8,960 9,088 9,940 11,360 11,928 13,440 13,632 14,910 15,904 17,040 18,176 19,880 22,720 23,856 26,880 27,264 29,820 31,808 34,080 39,760 45,440 47,712 54,528 59,640 63,616 68,160 79,520 90,880 95,424 119,280 127,232 136,320 159,040 190,848 238,560 272,640 318,080 381,696 477,120 636,160 954,240 and 1,908,480, with no remainder.
Since 1,908,480 cannot be divided by just 1 and 1,908,480, it is not a prime number.