A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1748760 can be evenly divided by 1 2 3 4 5 6 8 10 12 13 15 19 20 24 26 30 38 39 40 52 57 59 60 65 76 78 95 104 114 118 120 130 152 156 177 190 195 228 236 247 260 285 295 312 354 380 390 456 472 494 520 570 590 708 741 760 767 780 885 988 1,121 1,140 1,180 1,235 1,416 1,482 1,534 1,560 1,770 1,976 2,242 2,280 2,301 2,360 2,470 2,964 3,068 3,363 3,540 3,705 3,835 4,484 4,602 4,940 5,605 5,928 6,136 6,726 7,080 7,410 7,670 8,968 9,204 9,880 11,210 11,505 13,452 14,573 14,820 15,340 16,815 18,408 22,420 23,010 26,904 29,146 29,640 30,680 33,630 43,719 44,840 46,020 58,292 67,260 72,865 87,438 92,040 116,584 134,520 145,730 174,876 218,595 291,460 349,752 437,190 582,920 874,380 and 1,748,760, with no remainder.
Since 1,748,760 cannot be divided by just 1 and 1,748,760, it is not a prime number.