What about 1392?

Imagine you look at the first prime numbers and discover that 11 is a prime number. It is the first that consist of a multidigit number with just one particular digit - 1. There is a nice symmetry to it. You also realize that the number of digits in 11 (2) is also a prime number.

Imagine that a part of you get really curious at this point and your inner nerd ask: “Are there other prime numbers of just 1s where the length also is prime. That would be really mad crazy, right?

You start looking - and by looking I mean writing a program that look for you - checking as many as you can, adding a 1 at the end up to 10 000 digits, just to set a limit to the madness. You find that there are not that many at all, just five in total. Five out of 10 000.

2, 19, 23, 317 and 1031.

You look at the numbers, looking for any connections between them, apart from the already discovered unique feature they share.

Suddenly your brain add the numbers together. Or more realisticly, a calculator adds them and find 1392.

What about that. That is a new number. You let that number sink in by saying it quietly to yourself, because saying it out loud would cause people to find you weird, right? Not that looking at these numbers to begin with isn’t weird. Or is it?

Can there be anything special with this number? 1392? Some hidden attributes?

It is four digits, a perfectly fine pin code should you need a new one with a really exciting meaning and background! It is an abundant number, in binary it reads 10101110000 which has 11 digits, that is something? In hexadecimal it is 570 and the roman version is MCCCXCII. The kaprekars constant is reached after three steps starting with 1392. I assume a lot of interesting things happened in the year 1392 as well.

However, I don’t see anything particular special about this number, so I should probably just leave it like that…