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What does 987 point to in IL for the next

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CHICAGO
United States
Member #28557
December 18, 2005
111 Posts
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Posted: January 7, 2006, 11:28 am - IP Logged

 

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.