Considering what is known about memory, most telephone numbers are seven digits long because:

Most telephone numbers are seven digits long because this is the maximum amount of items which can be held in short term memory in a specific moment of time. If digits were more than seven it would have been difficult to memorize them and remember as short term memory refers to a very limited period of time.

it´s related to his charming character.

beauty is not everything, although we can joke that girls only care about the physical or material aspect, the truth is that a real woman looks at more important things, besides intelligence and personality, there are other attitudes that make irresistible to men who are 'unattractive'.

for example develop your sense of humor.