I have a question about the number 2 pencil

The number 2 pencil is the most popular and widely used pencil out there. But if it's the best pencil, then why do they call it the number 2 pencil?

I have a business idea, I want to make a company called The number 1 pencil, but i need a partner to help me.

It's important that you know good business strategies and are responsible with money. Does anyone want to help me?