A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1744680 can be evenly divided by 1 2 3 4 5 6 7 8 10 12 14 15 20 21 24 28 30 31 35 40 42 56 60 62 67 70 84 93 105 120 124 134 140 155 168 186 201 210 217 248 268 280 310 335 372 402 420 434 465 469 536 620 651 670 744 804 840 868 930 938 1,005 1,085 1,240 1,302 1,340 1,407 1,608 1,736 1,860 1,876 2,010 2,077 2,170 2,345 2,604 2,680 2,814 3,255 3,720 3,752 4,020 4,154 4,340 4,690 5,208 5,628 6,231 6,510 7,035 8,040 8,308 8,680 9,380 10,385 11,256 12,462 13,020 14,070 14,539 16,616 18,760 20,770 24,924 26,040 28,140 29,078 31,155 41,540 43,617 49,848 56,280 58,156 62,310 72,695 83,080 87,234 116,312 124,620 145,390 174,468 218,085 249,240 290,780 348,936 436,170 581,560 872,340 and 1,744,680, with no remainder.
Since 1,744,680 cannot be divided by just 1 and 1,744,680, it is not a prime number.