1439

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


 * The $228$th prime number.


 * 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 sequence of $6$ primes formed by doubling and adding one:
 * $\left({89, 179, 359, 719, 1439, 2879}\right)$