If I used the primary coil as an inductor, does the secondary coil affect it?
As long as the secondary remains open, it's basically not there magnetically or electrically.  In that case the primary will look like a regular inductor.

However, transformers don't usually make good inductors.  They are usually more lossy, it is often hard to get specs on just the inductance, and the frequency range may be not much more than the transformer was designed for.  Above that frequency, you may get significant core losses.