Concatenating prime factorsOne day I was bored and started concatenating natural numbers.
When I reached 7 I got more bored and started even to calculate its prime factors.
So I got 1234567 = 127 x 9721 and looked at it for a few minutes.
My boredom paid off because suddenly I discovered a palindrome.
Just concatenate the two prime factors and there it is 1279721.
Boredom now completely turned into exitement especially when I calculated the
difference between these two seven-digit numbers :
1279721 1234567 = 45154
I don't need to tell you what kind of a number that is, do I ?
Here is a spin-off from the above explained construction.
14432823441 = 3 x 3 x 281 x 313 x 18233
= 3328131318233 after concatenation of the prime factors.
I leave it up to you to post me larger palindromic solutions !
Please, consult also the following integer sequences from Sloane's database !
A046447 A046448 A046449 A046450
[ June 2001 ]
Terry Trotter (†)(email) from El Salvador (homepage) discovered
that the prime factors of the concatenation of 127 and 9721
or 1279721 are all three emirps (79 x 97 x 167) which upon
concatenation form yet another prime namely 7997167. (Prime Curios 1234567)
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