A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1404000 can be evenly divided by 1 2 3 4 5 6 8 9 10 12 13 15 16 18 20 24 25 26 27 30 32 36 39 40 45 48 50 52 54 60 65 72 75 78 80 90 96 100 104 108 117 120 125 130 135 144 150 156 160 180 195 200 208 216 225 234 240 250 260 270 288 300 312 325 351 360 375 390 400 416 432 450 468 480 500 520 540 585 600 624 650 675 702 720 750 780 800 864 900 936 975 1,000 1,040 1,080 1,125 1,170 1,200 1,248 1,300 1,350 1,404 1,440 1,500 1,560 1,625 1,755 1,800 1,872 1,950 2,000 2,080 2,160 2,250 2,340 2,400 2,600 2,700 2,808 2,925 3,000 3,120 3,250 3,375 3,510 3,600 3,744 3,900 4,000 4,320 4,500 4,680 4,875 5,200 5,400 5,616 5,850 6,000 6,240 6,500 6,750 7,020 7,200 7,800 8,775 9,000 9,360 9,750 10,400 10,800 11,232 11,700 12,000 13,000 13,500 14,040 14,625 15,600 17,550 18,000 18,720 19,500 21,600 23,400 26,000 27,000 28,080 29,250 31,200 35,100 36,000 39,000 43,875 46,800 52,000 54,000 56,160 58,500 70,200 78,000 87,750 93,600 108,000 117,000 140,400 156,000 175,500 234,000 280,800 351,000 468,000 702,000 and 1,404,000, with no remainder.
Since 1,404,000 cannot be divided by just 1 and 1,404,000, it is not a prime number.