All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info

Home > Numbers
Composite prime (Posted on 2015-02-24) Difficulty: 1 of 5
What is the smallest prime number such that all of its digits are composite?

See The Solution Submitted by Math Man    
Rating: 5.0000 (1 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
Solution | Comment 1 of 2
The composite digits are 4, 6, 8 and 9.
Clearly the number must have 2 or more digits so must end in 1, 3, 7, or 9.
Since 9 is the only composite, it must end in 9.
Checking 2 digit numbers with a composite first digit:
49 not prime
69 not prime 
89 is PRIME

  Posted by Jer on 2015-02-24 08:29:41
Please log in:
Login:
Password:
Remember me:
Sign up! | Forgot password


Search:
Search body:
Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (12)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2024 by Animus Pactum Consulting. All rights reserved. Privacy Information