A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 6254560 can be evenly divided by 1 2 4 5 8 10 13 16 20 26 31 32 40 52 62 65 80 97 104 124 130 155 160 194 208 248 260 310 388 403 416 485 496 520 620 776 806 970 992 1,040 1,240 1,261 1,552 1,612 1,940 2,015 2,080 2,480 2,522 3,007 3,104 3,224 3,880 4,030 4,960 5,044 6,014 6,305 6,448 7,760 8,060 10,088 12,028 12,610 12,896 15,035 15,520 16,120 20,176 24,056 25,220 30,070 32,240 39,091 40,352 48,112 50,440 60,140 64,480 78,182 96,224 100,880 120,280 156,364 195,455 201,760 240,560 312,728 390,910 481,120 625,456 781,820 1,250,912 1,563,640 3,127,280 and 6,254,560, with no remainder.
Since 6,254,560 cannot be divided by just 1 and 6,254,560, it is not a prime number.