php number_format显示小数

I have a number like this 18914439.4524345860 and I want to display that number like this 18.91

I have try the number_format function

$x = 18914439.4524345860;
echo number_format($x, 2, ".", ".");

and the result is

18.914.439.45 

how to show the number like this 18.91?

Thanks for your attention...

hope this help you :

$int = 18914439.4524345860/1000000;
echo round($int,2);
/* Output 18.91*/

18914439.4524345860 is a complete different number than 18.91, not just another representation.

You could divide by 1000000 first, and then use number_format:

$x = 18914439.4524345860;
echo number_format($x / 1000000, 2, ".", ".");