In mathematics, 1 is the multiplicative identity, meaning that any number multiplied by 1 equals the same number. 3 days agoalthough the number 1 used to be considered a prime number, it requires special treatment in so many definitions and applications involving primes greater than or equal to 2 that it is usually. Any number multiplied by 1 equals itself,.
Perfect number, a positive integer that is equal to the sum of its proper divisors.