67

This number is a prime.

Just showing those entries submitted by 'Green': (Click here to show all)

John Pilkins ©2003
+ Any digit n, 1 through 9, times 67 yields a 3-digit number (for the purpose of this discussion make 1*67 = 067), then the concatenation of the first and last digits of the product equals n times 7. E.g., 8*67 = 536 and 8*7 = 56. [Green]

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