131

Number
$131$ (one hundred and thirty-one) is:


 * The $32$nd prime number


 * The $12$th Sophie Germain prime after $2$, $3$, $5$, $11$, $23$, $29$, $41$, $53$, $83$, $89$, $113$:
 * $2 \times 131 + 1 = 263$, which is prime


 * The $7$th palindromic prime after $2$, $3$, $5$, $7$, $11$, $101$


 * The $15$th permutable prime after $2$, $3$, $5$, $7$, $11$, $13$, $17$, $31$, $37$, $71$, $73$, $79$, $97$, $113$


 * The decimal expansion of its reciprocal has the maximum period, that is, $130$:
 * $\dfrac 1 {131} = 0 \cdotp \dot 00763 \, 35877 \, 86259 \, 54198 \, 47328 \, 24427 \, 48091 \, 60305 \, 34351 \, 14503 \, 81679 \, 38931 \, 29770 \, 99236 \, 64122 \, 13740 \, 45801 \, 52671 \, 75572 \, 51908 \, 39694 \, 65648 \, 85496 \, 18320 \, 61068 \, 7022 \dot 9$


 * It also contains an equal number ($13$) of each of the digits from $0$ to $9$.


 * It is the $2$nd positive integer whose reciprocal has this property.

Also see