111,111

Number
$111 \, 111$ (one hundred and eleven thousand, one hundred and eleven) is:


 * $3 \times 7 \times 11 \times 13 \times 37$


 * A palindromic number whose square is also palindromic:


 * The $6$th repuint after $1$, $11$, $111$, $1111$, $11 \, 111$


 * The $10$th palindromic integer after $0$, $1$, $2$, $3$, $11$, $77$, $363$, $1111$, $2662$ which is the index of a palindromic triangular number
 * $T_{111 \, 111} = 6 \, 172 \, 882 \, 716$

Also see

 * Square of Small-Digit Palindromic Number is Palindromic