A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 5550000 can be evenly divided by 1 2 3 4 5 6 8 10 12 15 16 20 24 25 30 37 40 48 50 60 74 75 80 100 111 120 125 148 150 185 200 222 240 250 296 300 370 375 400 444 500 555 592 600 625 740 750 888 925 1,000 1,110 1,200 1,250 1,480 1,500 1,776 1,850 1,875 2,000 2,220 2,500 2,775 2,960 3,000 3,125 3,700 3,750 4,440 4,625 5,000 5,550 6,000 6,250 7,400 7,500 8,880 9,250 9,375 10,000 11,100 12,500 13,875 14,800 15,000 18,500 18,750 22,200 23,125 25,000 27,750 30,000 37,000 37,500 44,400 46,250 50,000 55,500 69,375 74,000 75,000 92,500 111,000 115,625 138,750 150,000 185,000 222,000 231,250 277,500 346,875 370,000 462,500 555,000 693,750 925,000 1,110,000 1,387,500 1,850,000 2,775,000 and 5,550,000, with no remainder.
Since 5,550,000 cannot be divided by just 1 and 5,550,000, it is not a prime number.