179

Number
$179$ (one hundred and seventy-nine) is:


 * The $41$st prime number


 * The $2$nd term after $89$ of the smallest Cunningham chain of the first kind of length $6$:
 * $\tuple {89, 179, 359, 719, 1439, 2879}$


 * The $10$th safe prime after $5$, $7$, $11$, $23$, $47$, $59$, $83$, $107$, $167$:
 * $179 = 2 \times 89 + 1$


 * The $1$st of the $13$th pair of twin primes, with $181$


 * The $14$th Sophie Germain prime after $2$, $3$, $5$, $11$, $23$, $29$, $41$, $53$, $83$, $89$, $113$, $131$, $173$:
 * $2 \times 179 + 1 = 359$, which is prime.


 * The $14$th emirp after $13$, $17$, $31$, $37$, $71$, $73$, $79$, $97$, $107$, $113$, $149$, $157$, $167$


 * The $15$th long period prime after $7$, $17$, $19$, $23$, $29$, $47$, $59$, $61$, $97$, $109$, $113$, $131$, $149$, $167$


 * The $35$th positive integer $n$ such that no factorial of an integer can end with $n$ zeroes.

Also see