what does This result mean?

Your calculator probably "overdosed" when it tried to calculate that "1.5" raised to a power greater than 31 million!! You probably got an "error" or "infinite" - or some such thing displayed.

Do you have any particular reason for trying to calculate such a large number??

If so...you might browse around the web......please be advised that trying to find an app that will display ALL the digits of this number is probably fruitless....

Here's a place you might start.....good luck!!

http://www.wolframalpha.com/examples/Math.html

The value of 1.5^31515999 exceeds the range of the calculator here, so it just returns ∞ for this.  Interestingly, instead of just returning ∞ for the whole calculation, it returns the result as a product of the result of (1000+1000/31536000) and infinity!! 

$$\left({\mathtt{1\,000}}{\mathtt{\,\small\textbf+\,}}{\frac{{\mathtt{1\,000}}}{{\mathtt{31\,536\,000}}}}\right){\mathtt{\,\times\,}}{{\mathtt{1.5}}}^{{\mathtt{31\,535\,999}}} = {\mathtt{1\,000.000\: \!031\: \!709\: \!791\: \!983\: \!8}}{\mathtt{\,\times\,}}\left(\infty\right)$$

Basically, you just have to interpret this as a number too big for the calculator here to compute!