A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 6907500 can be evenly divided by 1 2 3 4 5 6 9 10 12 15 18 20 25 30 36 45 50 60 75 90 100 125 150 180 225 250 300 307 375 450 500 614 625 750 900 921 1,125 1,228 1,250 1,500 1,535 1,842 1,875 2,250 2,500 2,763 3,070 3,684 3,750 4,500 4,605 5,526 5,625 6,140 7,500 7,675 9,210 11,052 11,250 13,815 15,350 18,420 22,500 23,025 27,630 30,700 38,375 46,050 55,260 69,075 76,750 92,100 115,125 138,150 153,500 191,875 230,250 276,300 345,375 383,750 460,500 575,625 690,750 767,500 1,151,250 1,381,500 1,726,875 2,302,500 3,453,750 and 6,907,500, with no remainder.
Since 6,907,500 cannot be divided by just 1 and 6,907,500, it is not a prime number.