187

Number
$187$ (one hundred and eighty-seven) is:


 * $11 \times 17$


 * The $11$th second pentagonal number after $2, 7, 15, 26, 40, 57, 77, 100, 126, 155$:
 * $187 = \dfrac {11 \left({3 \times 11 + 1}\right)} 2$


 * The $1$st of the $3$-digit integers $m$ which need the largest number of reverse-and-add process iterations ($23$) before reaching a palindromic number:
 * $187, 968, 1837, \ldots, 8713200023178$