Prime Curios!: 991

991
(another Prime Pages' Curiosity)

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991, 99991, and 9999991 are each prime. [Avrutin]

This number, as well as 331 and 661, are all prime. Note that the product of these three primes is a Carmichael Number. [Patterson]

The largest three-digit permutable prime.

991^2 = 982081 and 982 + 0 + 8 + 1 = 991. [Meller]

Florida angler Allen Ogle caught a 991-pound Hammerhead Shark on May 30, 1982.

(There is one curio for this number that has not yet been approved by an editor.)