A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 5219850 can be evenly divided by 1 2 3 5 6 10 15 17 23 25 30 34 46 50 51 69 75 85 89 102 115 138 150 170 178 230 255 267 345 391 425 445 510 534 575 690 782 850 890 1,150 1,173 1,275 1,335 1,513 1,725 1,955 2,047 2,225 2,346 2,550 2,670 3,026 3,450 3,910 4,094 4,450 4,539 5,865 6,141 6,675 7,565 9,078 9,775 10,235 11,730 12,282 13,350 15,130 19,550 20,470 22,695 29,325 30,705 34,799 37,825 45,390 51,175 58,650 61,410 69,598 75,650 102,350 104,397 113,475 153,525 173,995 208,794 226,950 307,050 347,990 521,985 869,975 1,043,970 1,739,950 2,609,925 and 5,219,850, with no remainder.
Since 5,219,850 cannot be divided by just 1 and 5,219,850, it is not a prime number.