A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 4264260 can be evenly divided by 1 2 3 4 5 6 7 10 11 12 13 14 15 20 21 22 26 28 30 33 35 39 42 44 52 55 60 65 66 70 71 77 78 84 91 105 110 130 132 140 142 143 154 156 165 182 195 210 213 220 231 260 273 284 286 308 330 355 364 385 390 420 426 429 455 462 497 546 572 660 710 715 770 780 781 852 858 910 923 924 994 1,001 1,065 1,092 1,155 1,365 1,420 1,430 1,491 1,540 1,562 1,716 1,820 1,846 1,988 2,002 2,130 2,145 2,310 2,343 2,485 2,730 2,769 2,860 2,982 3,003 3,124 3,692 3,905 4,004 4,260 4,290 4,615 4,620 4,686 4,970 5,005 5,460 5,467 5,538 5,964 6,006 6,461 7,455 7,810 8,580 9,230 9,372 9,940 10,010 10,153 10,934 11,076 11,715 12,012 12,922 13,845 14,910 15,015 15,620 16,401 18,460 19,383 20,020 20,306 21,868 23,430 25,844 27,335 27,690 29,820 30,030 30,459 32,305 32,802 38,766 40,612 46,860 50,765 54,670 55,380 60,060 60,918 64,610 65,604 71,071 77,532 82,005 96,915 101,530 109,340 121,836 129,220 142,142 152,295 164,010 193,830 203,060 213,213 284,284 304,590 328,020 355,355 387,660 426,426 609,180 710,710 852,852 1,066,065 1,421,420 2,132,130 and 4,264,260, with no remainder.
Since 4,264,260 cannot be divided by just 1 and 4,264,260, it is not a prime number.