A simple "Hello" seems to be the most common way for Americans to answer our phones. I have known a few families whose members would answer the phone with the "[family name] residence" phrase. However, had the last name been Smith, they would have said, "Smith residence," as opposed to. "the Smith's residence," leaving off the possessive "s".
As for answering the phone saying "X speaking," I've only known that to be done when one has been called to the phone by someone else who answered it. In other words, say my roommate had answered the phone and the caller asked for me. When I came to the phone, I might say, "Sarah speaking," or "This is Sarah," skipping the "hello". This is very common, though some would precede those phrases with "Hi" or "Hello".
I have never known a person to answer the phone by stating the number. That is common though on outgoing voicemail messages, yet, I've never heard the number alone stated first. Instead, the message will begin, "You have reached xxx-xxxx," and be followed by something like, "Sorry I missed your call. Please leave a message and I'll call you back."
These observations are based on common practices using home landline phones. In my experience, most Americans also most commonly answer their cell phones with, "Hello."
However, since most cell phones indicate who the caller is, one can and often does adapt the greeting based on that knowledge. If it it my husband calling, I might answer with, "Hi honey."
Imagine I was planning to meet my sister at the park. I am there and she is late. My cell phone rings, and I see that it's her. I might answer with, "Where are you?" Obviously, countless other opening phrases tailored to the caller and the circumstances are possible and common.