How do I block scammers from calling me?

I'm not dumb enough to fall for a scam but what annoys me is that I keep getting calls from people who claim to work for some corporation who say shit like "give us 5,000 dollars or you will be arrested." A week ago I had "Washington dc" call me and try to get me to pay a shit ton of money lol. How do I block em and how tf are they getting my number?

How do I block scammers from calling me?
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