What is Verizon's carrier code?

Could you please clarify for me, what exactly is Verizon's carrier code? I'm curious to understand the significance of this code and how it relates to their operations or services. Is it a unique identifier used by the telecommunications industry, or does it have a more specific purpose within the context of Verizon's business? Understanding this information would be helpful for me to better grasp the intricacies of the industry.