According to a study, mobile phone users on an average memorize just two numbers out of 50 in their contact list.
"In this day and age nobody needs to memorise phone numbers as we rarely have to dial a number anymore", The Telegraph quoted Mike Hodges of mobile security and backup software firm BullGuard, which commissioned the study, as saying.
The study also revealed that more than one in four people cannot recall their own phone number.
The report discovered that the lack of knowledge has landed one in three people in trouble because they were unable to contact a loved one after losing or breaking their phone.
Despite this, two thirds of respondents said they could remember phone numbers from years ago that are no longer even active.
The study also found more than a third of people continue to remember the phone number of their old houses, and touchingly one in ten people remember the numbers for their deceased grandparents.
Additionally, four out of ten said they actively try and remember phone numbers in case they ever lost them.
But 60 percent said that there is just no need to mentally store phone numbers anymore.
If a phone crashed or was lost, the average person would only remember two numbers, with mum's being the one number that people would most remember.
The study found that a clever 26 percent claimed that they have the numbers backed up on their computer, although a traditional 39 percent have written them down for safe keeping.
"Before mobile phones were common place, the majority of people would know their partners' phone number, as well as the contact details for their mum, dad, brother, sister, best friend and even their boss," Hodges said.
"But now we are much more reliant on our mobile phone's address book to help us get in touch with a loved one," he added.