Can I block my number when texting

I kinda doubt it, but I guess you can ask your carrier, as they handle SMS. As far as iMessage there is no setting for that. There really isn't one for SMS either, but again, the carrier controls SMS.

If you are using SMS text through your cellular carrier (very likely), then no, you cannot block your number.

Personally, I think this is a wonderful feature as it tends to minimize spam texts.