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Wednesday, September 12, 2007

73939133

73939133: I came across this fact. This is really cool. The specialty of this number is not just that it is a prime number but, every number that is produced by removing the last digit one by one is also a prime number. So, the following numbers are all prime.

7393913

739391

73939

7393

739

73

7


This is the largest such number known (as of today).

3 comments:

Karan said...

i don get it, wats the big shit? the principle works for any large no. with prime digits.

Shishir Pandey said...

No man it does not...and any ways 9 is not a prime number..so you idea about the prime digits does not work. Also take for example 3333. It contains all prime digits but is itself divisible by 3, 11, 1111,303....

ck said...

It is not a great stuff to proove that the highest number with that property is

1979339333

and there is also

373391399

higher than that number.