The book is now available! 987
(another Prime Pages' Curiosity)
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+ 987 is the only 3-digit number with consecutively decreasing digits such that when multiplied by the sum of its digits plus and minus one, the results are primes. I.e., 987*(9+8+7)-1 and 987*(9+8+7)+1 are primes. [Opao]

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




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