863

Number
$863$ (eight hundred and sixty-three) is:


 * The $150$th prime number


 * The smaller of the $6$th pair of primes whose prime gap is $14$:
 * $877 - 863 = 14$


 * The $23$rd safe prime after $5$, $7$, $11$, $23$, $47$, $59$, $83$, $107$, $167$, $179$, $227$, $263$, $347$, $359$, $383$, $467$, $479$, $503$, $563$, $587$, $719$, $839$:
 * $863 = 2 \times 431 + 1$