A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 5204808 can be evenly divided by 1 2 3 4 6 7 8 9 12 14 18 21 23 24 28 36 42 46 56 63 69 72 84 92 126 138 161 168 184 207 252 276 322 414 449 483 504 552 644 828 898 966 1,288 1,347 1,449 1,656 1,796 1,932 2,694 2,898 3,143 3,592 3,864 4,041 5,388 5,796 6,286 8,082 9,429 10,327 10,776 11,592 12,572 16,164 18,858 20,654 25,144 28,287 30,981 32,328 37,716 41,308 56,574 61,962 72,289 75,432 82,616 92,943 113,148 123,924 144,578 185,886 216,867 226,296 247,848 289,156 371,772 433,734 578,312 650,601 743,544 867,468 1,301,202 1,734,936 2,602,404 and 5,204,808, with no remainder.
Since 5,204,808 cannot be divided by just 1 and 5,204,808, it is not a prime number.