2 is the Arabic numeral representation of two objects in every mathematical base except binary (base 2) where it is represented by 10.

2 is represented by II in Roman numerals.

2 is the first even number and consequently what even numbers are exactly divisible by in order for them to be even.

2 is the only even prime number.

2 is in the Fibonacci sequence.

2 + 2 = 2 × 2