What does prime number actually mean? Find out inside PCMag's comprehensive tech and computer-related encyclopedia.

Today, people use complex computing networks to search for prime numbers with millions of digits. But early mathematicians were running these calculations by hand.

Modern mathematicians define prime numbers so that 1 isn’t prime, because it makes lots of results less awkward to state. An alternative magic square of prime numbers uses 5, 17, 29, 47, 59, 71,… ...

Math textbooks define a prime number as a whole number greater than one whose only positive divisors are only 1 and itself.

Today, people use complex computing networks to search for prime numbers with millions of digits. But early mathematicians were running these calculations by hand.