Primonumerophobia

Primonumerophobia is the fear of prime numbers. Many primonumerophobes may claim that encountering prime numbers may make them feel lonely due to the nature of prime numbers, while some may even believe that encountering prime numbers may summon entities to enslave them.

Most primonumerophobics would only fear the prime numbers less than 50 that most people would know, including 13, the most feared number. However the most feared number by primonumerophobics is 2, as it is the lone even prime number and closest to being lonely in quantity; see Duophobia.