A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 7072408 can be evenly divided by 1 2 4 7 8 14 17 19 23 28 34 38 46 56 68 76 92 119 133 136 152 161 184 238 266 289 322 323 391 437 476 532 578 644 646 782 874 952 1,064 1,156 1,288 1,292 1,564 1,748 2,023 2,261 2,312 2,584 2,737 3,059 3,128 3,496 4,046 4,522 5,474 5,491 6,118 6,647 7,429 8,092 9,044 10,948 10,982 12,236 13,294 14,858 16,184 18,088 21,896 21,964 24,472 26,588 29,716 38,437 43,928 46,529 52,003 53,176 59,432 76,874 93,058 104,006 126,293 153,748 186,116 208,012 252,586 307,496 372,232 416,024 505,172 884,051 1,010,344 1,768,102 3,536,204 and 7,072,408, with no remainder.
Since 7,072,408 cannot be divided by just 1 and 7,072,408, it is not a prime number.