A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 2460240 can be evenly divided by 1 2 3 4 5 6 8 9 10 12 15 16 17 18 20 24 27 30 34 36 40 45 48 51 54 60 67 68 72 80 85 90 102 108 120 134 135 136 144 153 170 180 201 204 216 240 255 268 270 272 306 335 340 360 402 408 432 459 510 536 540 603 612 670 680 720 765 804 816 918 1,005 1,020 1,072 1,080 1,139 1,206 1,224 1,340 1,360 1,530 1,608 1,809 1,836 2,010 2,040 2,160 2,278 2,295 2,412 2,448 2,680 3,015 3,060 3,216 3,417 3,618 3,672 4,020 4,080 4,556 4,590 4,824 5,360 5,695 6,030 6,120 6,834 7,236 7,344 8,040 9,045 9,112 9,180 9,648 10,251 11,390 12,060 12,240 13,668 14,472 16,080 17,085 18,090 18,224 18,360 20,502 22,780 24,120 27,336 28,944 30,753 34,170 36,180 36,720 41,004 45,560 48,240 51,255 54,672 61,506 68,340 72,360 82,008 91,120 102,510 123,012 136,680 144,720 153,765 164,016 205,020 246,024 273,360 307,530 410,040 492,048 615,060 820,080 1,230,120 and 2,460,240, with no remainder.
Since 2,460,240 cannot be divided by just 1 and 2,460,240, it is not a prime number.