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 Find my number (Posted on 2011-12-19)
My number:
1. Is a 3-digit number.
2. All its digits are prime digits.
3. A number formed by its 1st 2 digits is prime.
4. So is the number formed by its last 2 digits.
5. It is the smallest number satisfying the above conditions.

Find it.

Rem: The digits in my number do not have to be distinct.

Comments: ( Back to comment list | You must be logged in to post comments.)
 re(2): No problem (spoiler), if composite | Comment 3 of 10 |
(In reply to re: No problem (spoiler), if composite by Ady TZIDON)

The 1st condition limits the infinite number of possibilities to 900.
The 1st-2nd conditions limit the possible number of numbers to 64.
The 1st-3rd conditions limit the possible number of numbers to 20.
The 1st-4th conditions limit the possible number to five numbers.
These are: 237, 373, 537, 573, and 737.
The smallest of these five is 237, yet it is not prime. The next smallest, 373, is prime.

Edited on December 19, 2011, 11:37 pm
 Posted by Dej Mar on 2011-12-19 23:35:40

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