Some people might question how come I format my telephone numbers the way I do. The reason for this is to get close to ITU (International Telecommunications Union) standards. The only difference, is I would put a space between the country code, and the subscriber number. In example, my voicemail number is +1 9144491795. As you can see, there is a space after the 1 to show the country code. While this technically does not matter, I feel it is good to distinguish the country code since the country code varies from 1 – 3 numbers, and someone may not know if it is a 2 or 3 digit country code.
Exceptions to this is my contact cards. After the country code, I place a space after the 3rd and 6th number. This is to keep it as clean as possible, and will make it easier for someone in the US to recognize the number since this is relatively standard. I am not likely to give a contact card to someone outside of the NANP.