在自然数的大家庭中,有许许多多有趣的、值得关注的数,它们各有各的特性,从而使得自然数这个大家庭异彩纷呈,令人感叹!一、完全数古希腊大哲学家柏拉图在他的《共和国》一书中率先提出了“完全数”的概念,即:如果一个自然数的真因数(除去自身的因数称为真因数)之和等于它本身,那么,就称这个数是完全数. There are many interesting and noteworthy numbers in the large family of natural numbers, each of which has its own characteristics, which makes the family of natural numbers colorful and impressive. First, the number of ancient Greek philosophers, Plato, In his book The Republic, he first proposed the notion of “perfect number,” which means that if the sum of the true factors of a natural number (the factor excluding itself is called the true factor) equals itself, then this number is called Is the perfect number