66,056,806,460,865,066

Number
$66 \, 056 \, 806 \, 460 \, 865 \, 066$ is:


 * $2 \times 3 \times 7 \times 11 \times 1367 \times 6043 \times 17 \, 308 \, 303$


 * The $363 \, 474 \, 363$rd triangular number:
 * $66 \, 056 \, 806 \, 460 \, 865 \, 066 = \displaystyle \sum_{k \mathop = 1}^{363 \, 474 \, 363} k = \dfrac {363 \, 474 \, 363 \times \left({363 \, 474 \, 363 + 1}\right)} 2$


 * The $2$nd of $2$ known palindromic triangular numbers whose index is also palindromic:
 * $66 \, 056 \, 806 \, 460 \, 865 \, 066 = T_{363 \, 474 \, 363} = \dfrac {363 \, 474 \, 363 \times \left({363 \, 474 \, 363 + 1}\right)} 2$

Also see