97

Number
$97$ (ninety-seven) is:


 * The $25$th prime number


 * The larger of the $1$st pair of primes whose prime gap is $8$:
 * $97 - 89 = 8$


 * The $8$th emirp after $13$, $17$, $31$, $37$, $71$, $73$, $79$


 * The $9$th prime number after $7$, $17$, $19$, $23$, $29$, $47$, $59$, $61$ the period of whose reciprocal, when expressed in decimal notation, is of maximum length:
 * $\dfrac 1 {97} = $


 * The $13$th permutable prime after $2$, $3$, $5$, $7$, $11$, $13$, $17$, $31$, $37$, $71$, $73$, $79$


 * The $15$th prime $p$ after $11$, $23$, $29$, $37$, $41$, $43$, $47$, $53$, $59$, $67$, $71$, $73$, $79$, $83$ such that the Mersenne number $2^p - 1$ is composite


 * The $19$th happy number after $1$, $7$, $10$, $13$, $19$, $23$, $28$, $31$, $32$, $44$, $49$, $68$, $70$, $79$, $82$, $86$, $91$, $94$:
 * $97 \to 9^2 + 7^2 = 81 + 49 = 130 \to 1^2 + 3^2 + 0^2 = 1 + 9 + 0 = 10 \to 1^2 + 0^2 = 1$

Also see

 * Reciprocal of 97