Objective-C: Convert the entire double value to string without losing data

I have the following double value: 0.000900137869045636 which I would like to convert to a NSString.

I've tried the following code, but no matter what, it rounds the value to this: 0.000900138

[NSString stringWithFormat:@"%.20lf", [currentLocation coordinate].latitude];

What should I do to keep the double number as it is?

Thank you.