A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 6480600 can be evenly divided by 1 2 3 4 5 6 7 8 10 12 14 15 20 21 24 25 28 30 35 40 42 50 56 60 70 75 84 100 105 120 140 150 168 175 200 210 280 300 350 420 525 600 700 840 1,050 1,400 1,543 2,100 3,086 4,200 4,629 6,172 7,715 9,258 10,801 12,344 15,430 18,516 21,602 23,145 30,860 32,403 37,032 38,575 43,204 46,290 54,005 61,720 64,806 77,150 86,408 92,580 108,010 115,725 129,612 154,300 162,015 185,160 216,020 231,450 259,224 270,025 308,600 324,030 432,040 462,900 540,050 648,060 810,075 925,800 1,080,100 1,296,120 1,620,150 2,160,200 3,240,300 and 6,480,600, with no remainder.
Since 6,480,600 cannot be divided by just 1 and 6,480,600, it is not a prime number.