A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1745280 can be evenly divided by 1 2 3 4 5 6 8 9 10 12 15 16 18 20 24 27 30 32 36 40 45 48 54 60 64 72 80 90 96 101 108 120 128 135 144 160 180 192 202 216 240 270 288 303 320 360 384 404 432 480 505 540 576 606 640 720 808 864 909 960 1,010 1,080 1,152 1,212 1,440 1,515 1,616 1,728 1,818 1,920 2,020 2,160 2,424 2,727 2,880 3,030 3,232 3,456 3,636 4,040 4,320 4,545 4,848 5,454 5,760 6,060 6,464 7,272 8,080 8,640 9,090 9,696 10,908 12,120 12,928 13,635 14,544 16,160 17,280 18,180 19,392 21,816 24,240 27,270 29,088 32,320 36,360 38,784 43,632 48,480 54,540 58,176 64,640 72,720 87,264 96,960 109,080 116,352 145,440 174,528 193,920 218,160 290,880 349,056 436,320 581,760 872,640 and 1,745,280, with no remainder.
Since 1,745,280 cannot be divided by just 1 and 1,745,280, it is not a prime number.