263

Number
$263$ (two hundred and sixty-three) is:


 * The $56$th prime number


 * The $7$th balanced prime after $5, 53, 157, 173, 211, 257$:
 * $263 = \dfrac {257 + 269} 2$


 * The $12$th safe prime after $5$, $7$, $11$, $23$, $47$, $59$, $83$, $107$, $167$, $179$, $227$:
 * $263 = 2 \times 131 + 1$


 * The $22$nd long period prime after $7$, $17$, $19$, $23$, $29$, $\ldots$, $181$, $193$, $223$, $229$, $233$, $257$


 * The $41$st happy number after $1$, $7$, $10$, $13$, $19$, $23$, $\ldots$, $188$, $190$, $192$, $193$, $203$, $208$, $219$, $226$, $230$, $236$, $239$, $262$:
 * $263 \to 2^2 + 6^2 + 3^2 = 4 + 36 + 9 = 49 \to 4^2 + 9^2 = 16 + 81 = 97 \to 9^2 + 7^2 = 81 + 49 = 130 \to 1^2 + 3^2 + 0^2 = 1 + 9 + 0 = 10 \to 1^2 + 0^2 = 1$

Also see