197

Number
$197$ (one hundred and ninety-seven) is:


 * The $45$th prime number


 * The $1$st of the $15$th pair of twin primes, with $199$


 * The $7$th Keith number after $14$, $19$, $28$, $47$, $61$, $75$:
 * $1$, $9$, $7$, $17$, $33$, $57$, $107$, $197$, $\ldots$


 * The $6$th prime number of the form $n^2 + 1$ after $2$, $5$, $17$, $37$, $101$:
 * $197 = 14^2 + 1$