A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 4586890 can be evenly divided by 1 2 5 7 10 11 14 22 23 35 37 46 49 55 70 74 77 98 110 115 154 161 185 230 245 253 259 322 370 385 407 490 506 518 539 770 805 814 851 1,078 1,127 1,265 1,295 1,610 1,702 1,771 1,813 2,035 2,254 2,530 2,590 2,695 2,849 3,542 3,626 4,070 4,255 5,390 5,635 5,698 5,957 8,510 8,855 9,065 9,361 11,270 11,914 12,397 14,245 17,710 18,130 18,722 19,943 24,794 28,490 29,785 39,886 41,699 46,805 59,570 61,985 65,527 83,398 93,610 99,715 123,970 131,054 199,430 208,495 327,635 416,990 458,689 655,270 917,378 2,293,445 and 4,586,890, with no remainder.
Since 4,586,890 cannot be divided by just 1 and 4,586,890, it is not a prime number.