A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 6242775 can be evenly divided by 1 3 5 7 11 15 21 23 25 33 35 47 55 69 75 77 105 115 141 161 165 175 231 235 253 275 329 345 385 483 517 525 575 705 759 805 825 987 1,081 1,155 1,175 1,265 1,551 1,645 1,725 1,771 1,925 2,415 2,585 3,243 3,525 3,619 3,795 4,025 4,935 5,313 5,405 5,775 6,325 7,567 7,755 8,225 8,855 10,857 11,891 12,075 12,925 16,215 18,095 18,975 22,701 24,675 26,565 27,025 35,673 37,835 38,775 44,275 54,285 59,455 81,075 83,237 90,475 113,505 132,825 178,365 189,175 249,711 271,425 297,275 416,185 567,525 891,825 1,248,555 2,080,925 and 6,242,775, with no remainder.
Since 6,242,775 cannot be divided by just 1 and 6,242,775, it is not a prime number.