A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 6424000 can be evenly divided by 1 2 4 5 8 10 11 16 20 22 25 32 40 44 50 55 64 73 80 88 100 110 125 146 160 176 200 220 250 275 292 320 352 365 400 440 500 550 584 704 730 800 803 880 1,000 1,100 1,168 1,375 1,460 1,600 1,606 1,760 1,825 2,000 2,200 2,336 2,750 2,920 3,212 3,520 3,650 4,000 4,015 4,400 4,672 5,500 5,840 6,424 7,300 8,000 8,030 8,800 9,125 11,000 11,680 12,848 14,600 16,060 17,600 18,250 20,075 22,000 23,360 25,696 29,200 32,120 36,500 40,150 44,000 51,392 58,400 64,240 73,000 80,300 88,000 100,375 116,800 128,480 146,000 160,600 200,750 256,960 292,000 321,200 401,500 584,000 642,400 803,000 1,284,800 1,606,000 3,212,000 and 6,424,000, with no remainder.
Since 6,424,000 cannot be divided by just 1 and 6,424,000, it is not a prime number.