A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 500940 can be evenly divided by 1 2 3 4 5 6 9 10 11 12 15 18 20 22 23 30 33 36 44 45 46 55 60 66 69 90 92 99 110 115 121 132 138 165 180 198 207 220 230 242 253 276 330 345 363 396 414 460 484 495 506 605 660 690 726 759 828 990 1,012 1,035 1,089 1,210 1,265 1,380 1,452 1,518 1,815 1,980 2,070 2,178 2,277 2,420 2,530 2,783 3,036 3,630 3,795 4,140 4,356 4,554 5,060 5,445 5,566 7,260 7,590 8,349 9,108 10,890 11,132 11,385 13,915 15,180 16,698 21,780 22,770 25,047 27,830 33,396 41,745 45,540 50,094 55,660 83,490 100,188 125,235 166,980 250,470 and 500,940, with no remainder.
Since 500,940 cannot be divided by just 1 and 500,940, it is not a prime number.