A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1494240 can be evenly divided by 1 2 3 4 5 6 8 10 11 12 15 16 20 22 24 30 32 33 40 44 48 55 60 66 80 88 96 110 120 132 160 165 176 220 240 264 283 330 352 440 480 528 566 660 849 880 1,056 1,132 1,320 1,415 1,698 1,760 2,264 2,640 2,830 3,113 3,396 4,245 4,528 5,280 5,660 6,226 6,792 8,490 9,056 9,339 11,320 12,452 13,584 15,565 16,980 18,678 22,640 24,904 27,168 31,130 33,960 37,356 45,280 46,695 49,808 62,260 67,920 74,712 93,390 99,616 124,520 135,840 149,424 186,780 249,040 298,848 373,560 498,080 747,120 and 1,494,240, with no remainder.
Since 1,494,240 cannot be divided by just 1 and 1,494,240, it is not a prime number.