A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 8253900 can be evenly divided by 1 2 3 4 5 6 9 10 12 15 18 20 25 27 30 36 45 50 54 60 75 81 90 100 108 135 150 162 180 225 270 300 324 405 450 540 675 810 900 1,019 1,350 1,620 2,025 2,038 2,700 3,057 4,050 4,076 5,095 6,114 8,100 9,171 10,190 12,228 15,285 18,342 20,380 25,475 27,513 30,570 36,684 45,855 50,950 55,026 61,140 76,425 82,539 91,710 101,900 110,052 137,565 152,850 165,078 183,420 229,275 275,130 305,700 330,156 412,695 458,550 550,260 687,825 825,390 917,100 1,375,650 1,650,780 2,063,475 2,751,300 4,126,950 and 8,253,900, with no remainder.
Since 8,253,900 cannot be divided by just 1 and 8,253,900, it is not a prime number.