1439

Number
$1439$ (one thousand, four hundred and thirty-nine) is:


 * The $228$th prime number.


 * The smaller of the $20$th pair of primes whose prime gap is $8$:
 * $1447 - 1439 = 8$


 * The $32$nd safe prime after $5$, $7$, $11$, $23$, $47$, $\ldots$, $839$, $863$, $887$, $983$, $1019$, $1187$, $1283$, $1307$, $1319$, $1367$:
 * $1439 = 2 \times 719 + 1$


 * The $47$th Sophie Germain prime after $2$, $3$, $5$, $11$, $23$, $29$, $41$, $\ldots$, $1031$, $1049$, $1103$, $1223$, $1229$, $1289$, $1409$:
 * $2 \times 1439 + 1 = 2879$, which is prime.


 * The $5$th term after $89$, $179$, $359$, $719$ of the smallest Cunningham chain of the first kind of length $6$:
 * $\tuple {89, 179, 359, 719, 1439, 2879}$