509

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Number

$509$ (five hundred and nine) is:

The $97$th prime number

The $8$th obstinate number after $1$, $127$, $149$, $251$, $331$, $337$, $373$

The $26$th Sophie Germain prime after $2$, $3$, $5$, $11$, $23$, $29$, $41$, $\ldots$, $233$, $239$, $251$, $281$, $293$, $359$, $419$, $431$, $443$, $491$:

$2 \times 509 + 1 = 1019$, which is prime.

The $37$th long period prime after $7$, $17$, $19$, $23$, $29$, $\ldots$, $383$, $389$, $419$, $433$, $461$, $487$, $491$, $499$, $503$

Also see

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• Previous  ... Next: Sophie Germain Prime

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