A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1446480 can be evenly divided by 1 2 3 4 5 6 7 8 9 10 12 14 15 16 18 20 21 24 28 30 35 36 40 41 42 45 48 49 56 60 63 70 72 80 82 84 90 98 105 112 120 123 126 140 144 147 164 168 180 196 205 210 240 245 246 252 280 287 294 315 328 336 360 369 392 410 420 441 490 492 504 560 574 588 615 630 656 720 735 738 784 820 840 861 882 980 984 1,008 1,148 1,176 1,230 1,260 1,435 1,470 1,476 1,640 1,680 1,722 1,764 1,845 1,960 1,968 2,009 2,205 2,296 2,352 2,460 2,520 2,583 2,870 2,940 2,952 3,280 3,444 3,528 3,690 3,920 4,018 4,305 4,410 4,592 4,920 5,040 5,166 5,740 5,880 5,904 6,027 6,888 7,056 7,380 8,036 8,610 8,820 9,840 10,045 10,332 11,480 11,760 12,054 12,915 13,776 14,760 16,072 17,220 17,640 18,081 20,090 20,664 22,960 24,108 25,830 29,520 30,135 32,144 34,440 35,280 36,162 40,180 41,328 48,216 51,660 60,270 68,880 72,324 80,360 90,405 96,432 103,320 120,540 144,648 160,720 180,810 206,640 241,080 289,296 361,620 482,160 723,240 and 1,446,480, with no remainder.
Since 1,446,480 cannot be divided by just 1 and 1,446,480, it is not a prime number.