@Francisco. The big book of Numerology: the Hidden Meaning of Numbers and Letters, by Shirley Blackwell Lawrence.
F is a descendant from the Hebrew letter Vau (V). All 6 letters, F, O, and X, are good teachers, for 6’s are concerned with their communities and want to be of value. They understand the law and desire to uphold it. They care about their environment and the people with whom they associate. Some are drawn to politics, some to counseling, and many to teaching itself. The 6 also represents the voice that must be heard, and is important to 6’s in their careers. They will take on responsibilities as their duty. This propensity toward responsibility can be seen in the shape of the letter. F carries a double cross. Everyone comes to them with their problems, and they will “carry the load” for them and take an active role in helping all they can, or just worry about it. F is not as well balanced as E. It needs to be calm and to avoid confusion. Being 6, it wants to finish things and do so in a peaceful atmosphere. The two horizontal lines of the F are like arms outstretched to help those near them, and 6 is a numerical vibration of service. They are most fulfilled when they accomplish something that is of benefit to other people, whether their own family, friends, or community. F is the sixth letter, and 6 desires artistic surroundings. This number is prevalent in the arts. The 6 may enter a field of music, decorating, acting, or performing, which is, in a sense, serving others. A good performance brings joy to many people. F has an open mind and a sixth sense. It is similar to the letter P, the only difference being that the F is open to new ideas. P is opinionated and has a closed mind. (See the closed-in circle at the top of P?) It is the 16th letter, which is 7, and 7 turns its back on the other numbers and chooses its own counsel. F’s are idealistic and as a rule they wish to express beauty. Their calm exteriors give them a kind, parental look. The negative F carries the responsibility trait to an extreme. This is the meddlesome know-it-all who thinks no one else is right, that he/she alone has all the answers, and is smugly self-righteous. This is the voice that must be heard, which, when negative, will display a stubborn streak, using the voice as a silent weapon and not speaking for days. Those who live mainly on the negative polarity of this vibration are people who want to control their families and friends. They can be tyrants and not even realize it because they are so sure that they are absolutely right. By their stubbornness, they make many people unhappy and uncomfortable in their presence. Otherwise F is a happy family vibration. It stands for Family, Fatherliness, and Fidelity. F can be very passionate. It expresses the full 6 vibration, which is the number of Venus, the planet of love. It will mother or smother.