A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 7708000 can be evenly divided by 1 2 4 5 8 10 16 20 25 32 40 41 47 50 80 82 94 100 125 160 164 188 200 205 235 250 328 376 400 410 470 500 656 752 800 820 940 1,000 1,025 1,175 1,312 1,504 1,640 1,880 1,927 2,000 2,050 2,350 3,280 3,760 3,854 4,000 4,100 4,700 5,125 5,875 6,560 7,520 7,708 8,200 9,400 9,635 10,250 11,750 15,416 16,400 18,800 19,270 20,500 23,500 30,832 32,800 37,600 38,540 41,000 47,000 48,175 61,664 77,080 82,000 94,000 96,350 154,160 164,000 188,000 192,700 240,875 308,320 385,400 481,750 770,800 963,500 1,541,600 1,927,000 3,854,000 and 7,708,000, with no remainder.
Since 7,708,000 cannot be divided by just 1 and 7,708,000, it is not a prime number.