A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3713580 can be evenly divided by 1 2 3 4 5 6 9 10 12 13 15 18 20 23 26 27 30 36 39 45 46 52 54 60 65 69 78 90 92 108 115 117 130 135 138 156 180 195 207 230 234 260 270 276 299 345 351 390 414 460 468 529 540 585 598 621 690 702 780 828 897 1,035 1,058 1,170 1,196 1,242 1,380 1,404 1,495 1,587 1,755 1,794 2,070 2,116 2,340 2,484 2,645 2,691 2,990 3,105 3,174 3,510 3,588 4,140 4,485 4,761 5,290 5,382 5,980 6,210 6,348 6,877 7,020 7,935 8,073 8,970 9,522 10,580 10,764 12,420 13,455 13,754 14,283 15,870 16,146 17,940 19,044 20,631 23,805 26,910 27,508 28,566 31,740 32,292 34,385 40,365 41,262 47,610 53,820 57,132 61,893 68,770 71,415 80,730 82,524 95,220 103,155 123,786 137,540 142,830 161,460 185,679 206,310 247,572 285,660 309,465 371,358 412,620 618,930 742,716 928,395 1,237,860 1,856,790 and 3,713,580, with no remainder.
Since 3,713,580 cannot be divided by just 1 and 3,713,580, it is not a prime number.