A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 2471560 can be evenly divided by 1 2 4 5 7 8 10 13 14 20 26 28 35 40 49 52 56 65 70 91 97 98 104 130 140 182 194 196 245 260 280 364 388 392 455 485 490 520 637 679 728 776 910 970 980 1,261 1,274 1,358 1,820 1,940 1,960 2,522 2,548 2,716 3,185 3,395 3,640 3,880 4,753 5,044 5,096 5,432 6,305 6,370 6,790 8,827 9,506 10,088 12,610 12,740 13,580 17,654 19,012 23,765 25,220 25,480 27,160 35,308 38,024 44,135 47,530 50,440 61,789 70,616 88,270 95,060 123,578 176,540 190,120 247,156 308,945 353,080 494,312 617,890 1,235,780 and 2,471,560, with no remainder.
Since 2,471,560 cannot be divided by just 1 and 2,471,560, it is not a prime number.