A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 4558140 can be evenly divided by 1 2 3 4 5 6 9 10 12 15 18 20 23 27 30 36 45 46 54 60 69 90 92 108 115 135 138 180 207 230 270 276 345 367 414 460 540 621 690 734 828 1,035 1,101 1,242 1,380 1,468 1,835 2,070 2,202 2,484 3,105 3,303 3,670 4,140 4,404 5,505 6,210 6,606 7,340 8,441 9,909 11,010 12,420 13,212 16,515 16,882 19,818 22,020 25,323 33,030 33,764 39,636 42,205 49,545 50,646 66,060 75,969 84,410 99,090 101,292 126,615 151,938 168,820 198,180 227,907 253,230 303,876 379,845 455,814 506,460 759,690 911,628 1,139,535 1,519,380 2,279,070 and 4,558,140, with no remainder.
Since 4,558,140 cannot be divided by just 1 and 4,558,140, it is not a prime number.