A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1252350 can be evenly divided by 1 2 3 5 6 9 10 11 15 18 22 23 25 30 33 45 46 50 55 66 69 75 90 99 110 115 121 138 150 165 198 207 225 230 242 253 275 330 345 363 414 450 495 506 550 575 605 690 726 759 825 990 1,035 1,089 1,150 1,210 1,265 1,518 1,650 1,725 1,815 2,070 2,178 2,277 2,475 2,530 2,783 3,025 3,450 3,630 3,795 4,554 4,950 5,175 5,445 5,566 6,050 6,325 7,590 8,349 9,075 10,350 10,890 11,385 12,650 13,915 16,698 18,150 18,975 22,770 25,047 27,225 27,830 37,950 41,745 50,094 54,450 56,925 69,575 83,490 113,850 125,235 139,150 208,725 250,470 417,450 626,175 and 1,252,350, with no remainder.
Since 1,252,350 cannot be divided by just 1 and 1,252,350, it is not a prime number.