A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 8163900 can be evenly divided by 1 2 3 4 5 6 9 10 12 15 18 20 25 30 36 45 47 50 60 75 90 94 100 141 150 180 188 193 225 235 282 300 386 423 450 470 564 579 705 772 846 900 940 965 1,158 1,175 1,410 1,692 1,737 1,930 2,115 2,316 2,350 2,820 2,895 3,474 3,525 3,860 4,230 4,700 4,825 5,790 6,948 7,050 8,460 8,685 9,071 9,650 10,575 11,580 14,100 14,475 17,370 18,142 19,300 21,150 27,213 28,950 34,740 36,284 42,300 43,425 45,355 54,426 57,900 81,639 86,850 90,710 108,852 136,065 163,278 173,700 181,420 226,775 272,130 326,556 408,195 453,550 544,260 680,325 816,390 907,100 1,360,650 1,632,780 2,040,975 2,721,300 4,081,950 and 8,163,900, with no remainder.
Since 8,163,900 cannot be divided by just 1 and 8,163,900, it is not a prime number.