1111

Number
$1111$ (one thousand, one hundred and eleven) is:


 * $11 \times 101$


 * The $4$th repuint after $1$, $11$, $111$


 * The $8$th palindromic integer after $0$, $1$, $2$, $3$, $11$, $77$, $363$ which is the index of a palindromic triangular number
 * $T_{1111} = 617 \, 716$


 * The $13$th palindromic integer after $0$, $1$, $2$, $3$, $11$, $22$, $101$, $111$, $121$, $202$, $212$, $1001$ whose square is also palindromic integer
 * $1111^2 = 1 \, 234 \, 321$


 * The $35$th Zuckerman number after $1$, $2$, $3$, $4$, $5$, $6$, $7$, $8$, $9$, $11$, $12$, $\ldots$, $216$, $224$, $312$, $315$, $384$, $432$, $612$, $624$, $672$, $735$, $816$:
 * $1111 = 1111 \times 1 = 1111 \times \paren {1 \times 1 \times 1 \times 1}$


 * The $51$st Smith number after $4$, $22$, $27$, $58$, $\ldots$, $778$, $825$, $852$, $895$, $913$, $915$, $922$, $958$, $985$, $1086$:
 * $1 + 1 + 1 + 1 = 1 + 1 + 1 + 0 + 1 = 4$


 * $1111 = 56^2 - 45^2$

Also see

 * Difference between Two Squares equal to Repunit