A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 535500 can be evenly divided by 1 2 3 4 5 6 7 9 10 12 14 15 17 18 20 21 25 28 30 34 35 36 42 45 50 51 60 63 68 70 75 84 85 90 100 102 105 119 125 126 140 150 153 170 175 180 204 210 225 238 250 252 255 300 306 315 340 350 357 375 420 425 450 476 500 510 525 595 612 630 700 714 750 765 850 875 900 1,020 1,050 1,071 1,125 1,190 1,260 1,275 1,428 1,500 1,530 1,575 1,700 1,750 1,785 2,100 2,125 2,142 2,250 2,380 2,550 2,625 2,975 3,060 3,150 3,500 3,570 3,825 4,250 4,284 4,500 5,100 5,250 5,355 5,950 6,300 6,375 7,140 7,650 7,875 8,500 8,925 10,500 10,710 11,900 12,750 14,875 15,300 15,750 17,850 19,125 21,420 25,500 26,775 29,750 31,500 35,700 38,250 44,625 53,550 59,500 76,500 89,250 107,100 133,875 178,500 267,750 and 535,500, with no remainder.
Since 535,500 cannot be divided by just 1 and 535,500, it is not a prime number.