30,416,261,403

Number
$30 \, 416 \, 261 \, 403$ is:


 * $3 \times 11 \times 37 \times 101 \times 246 \, 643$


 * The $11$th palindromic triangular number after $0$, $1$, $3$, $6$, $66$, $3003$, $66 \, 066$, $617 \, 716$, $3 \, 544 \, 453$, $6 \, 172 \, 882 \, 716$ whose index is itself palindromic:
 * $30 \, 416 \, 261 \, 403 = T_{246 \, 642}$


 * The $246 \, 642$nd triangular number:
 * $30 \, 416 \, 261 \, 403 = \dfrac {246 \, 642 \times \paren {246 \, 642 + 1} } 2$