638,523,249

Number
$638 \, 523 \, 249$ is:


 * $3 \times 7 \times 13 \times 107 \times 21 \, 859$


 * The $3$rd known positive integer whose fourth power can be expressed as the sum of $3$ fourth powers, thus refuting the Euler Quartic Conjecture:
 * $638 \, 523 \, 249^4 = 630 \, 662 \, 624^4 + 275 \, 156 \, 240^4 + 219 \, 076 \, 465^4$