A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 450450 can be evenly divided by 1 2 3 5 6 7 9 10 11 13 14 15 18 21 22 25 26 30 33 35 39 42 45 50 55 63 65 66 70 75 77 78 90 91 99 105 110 117 126 130 143 150 154 165 175 182 195 198 210 225 231 234 273 275 286 315 325 330 350 385 390 429 450 455 462 495 525 546 550 585 630 650 693 715 770 819 825 858 910 975 990 1,001 1,050 1,155 1,170 1,287 1,365 1,386 1,430 1,575 1,638 1,650 1,925 1,950 2,002 2,145 2,275 2,310 2,475 2,574 2,730 2,925 3,003 3,150 3,465 3,575 3,850 4,095 4,290 4,550 4,950 5,005 5,775 5,850 6,006 6,435 6,825 6,930 7,150 8,190 9,009 10,010 10,725 11,550 12,870 13,650 15,015 17,325 18,018 20,475 21,450 25,025 30,030 32,175 34,650 40,950 45,045 50,050 64,350 75,075 90,090 150,150 225,225 and 450,450, with no remainder.
Since 450,450 cannot be divided by just 1 and 450,450, it is not a prime number.