11,111,111,111,111,111,111,111

Number
$11 \, 111 \, 111 \, 111 \, 111 \, 111 \, 111 \, 111$ is:


 * A prime number


 * The $23$rd repunit


 * The $3$rd repunit prime


 * The $24$th permutable prime after $2$, $3$, $5$, $7$, $11$, $13$, $17$, $31$, $37$, $71$, $73$, $79$, $97$, $113$, $131$, $199$, $311$, $337$, $373$, $733$, $919$, $991$, $1 \, 111 \, 111 \, 111 \, 111 \, 111 \, 111$

Also see