Harry's name is because J.K. Rowling, the author of Numbers, liked it when she was very young. She thinks it's good. It's like giving this name to her little daughter, but because the author J.K. Rowling wants to give all the rights to her protagonist, she gives her children other names.

The surname is Porter because J.K. Rowling, the author of Decimal, has a neighbor's child named Porter. Playing together since childhood has great imagination. They all know that there is magic in the world, and they become best friends. So when the author wrote Harry Potter as an adult, he used the surname of his childhood friend, who was his best childhood friend.