A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3082590 can be evenly divided by 1 2 3 5 6 7 9 10 14 15 18 21 27 30 35 42 45 49 54 63 70 90 98 105 126 135 147 189 210 233 245 270 294 315 378 441 466 490 630 699 735 882 945 1,165 1,323 1,398 1,470 1,631 1,890 2,097 2,205 2,330 2,646 3,262 3,495 4,194 4,410 4,893 6,291 6,615 6,990 8,155 9,786 10,485 11,417 12,582 13,230 14,679 16,310 20,970 22,834 24,465 29,358 31,455 34,251 44,037 48,930 57,085 62,910 68,502 73,395 88,074 102,753 114,170 146,790 171,255 205,506 220,185 308,259 342,510 440,370 513,765 616,518 1,027,530 1,541,295 and 3,082,590, with no remainder.
Since 3,082,590 cannot be divided by just 1 and 3,082,590, it is not a prime number.