Number Portability: POTS, VoIP, and Cellular

I haven't found answers to most of these questions:

1. Can a VoIP number be ported to cellular?

1. Can a VoIP number be ported to POTS?

2. Can a VoIP number be ported to another VoIP provider?

1. Can a cellular number be ported to POTS?

2. Can a cellular number be ported to VoIP?

1. Can a cellular number be ported to another cellular provider? (I think that the answer is yes.)

2. Can a POTS number be ported to cellular? (I think that the answer is yes.)

1. Can a POTS number be ported to VoIP? (I think that the answer is yes.)

Can you provide answers?

Can you direct me to the answers on the Internet?