Who called from 4154292251

they are texting me inappropriate things

Do not respond to unwanted texts or emails from questionable sources. Several mobile service providers will allow you to report unwanted spam texts by simply texting/forwarding it to 7726 (or “spam”) to enable the providers to prevent future unwanted texts from the specific sender.

(If your provider is ATT, try the code "block")

Source:
http://www.fcc.gov/guides/spam-unwanted-text-messages-and-email

More info:
http://en.wikipedia.org/wiki/Mobile_phone_spam
http://blog.usa.gov/post/89152807112/protect-yourself-from-text-message-spam

However, in many cases, the text origin, as seen on your phone, is faked.  The internet domain does not exist, or the phone number may have been spoofed.

Rec'd an inappropriate text from this #.  Make it stop!

Received inappropriate text at 4am.

For AT&T follow the instructions here to report and then block:

http://www.att.com/esupport/article.jsp?sid=KB115812