A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 6259500 can be evenly divided by 1 2 3 4 5 6 9 10 12 13 15 18 20 25 26 30 36 39 45 50 52 60 65 75 78 90 100 107 117 125 130 150 156 180 195 214 225 234 250 260 300 321 325 375 390 428 450 468 500 535 585 642 650 750 780 900 963 975 1,070 1,125 1,170 1,284 1,300 1,391 1,500 1,605 1,625 1,926 1,950 2,140 2,250 2,340 2,675 2,782 2,925 3,210 3,250 3,852 3,900 4,173 4,500 4,815 4,875 5,350 5,564 5,850 6,420 6,500 6,955 8,025 8,346 9,630 9,750 10,700 11,700 12,519 13,375 13,910 14,625 16,050 16,692 19,260 19,500 20,865 24,075 25,038 26,750 27,820 29,250 32,100 34,775 40,125 41,730 48,150 50,076 53,500 58,500 62,595 69,550 80,250 83,460 96,300 104,325 120,375 125,190 139,100 160,500 173,875 208,650 240,750 250,380 312,975 347,750 417,300 481,500 521,625 625,950 695,500 1,043,250 1,251,900 1,564,875 2,086,500 3,129,750 and 6,259,500, with no remainder.
Since 6,259,500 cannot be divided by just 1 and 6,259,500, it is not a prime number.