Numbers / 2

The Number 2

2 is prime: only 1 and 2 divide it evenly; the next prime after 2 is 3. 2's proper divisors total just 1, 1 short of 2, the deficient case most of 2's neighbors share too. 2 is also a Fibonacci number, since 1 + 1 = 2. 2 has a digit sum of 2; for 2, the digital root works out to 2. 2 shares no factor with 2-12; 2's own divisors start beyond that range. 2 is 10 in binary and 2 in hex; as a Roman numeral it's II.