Two (2) is a positive integer one more than 1 and one less than 3.


Two is the 1st prime number (next is 3), and the only even prime number.

Taking the second power of a number is called taking its square.

Two is the base of the binary system, used in computers.

2 is a Mersenne exponent, producing the prime 3. The next exponent is 3.

Powers of two are important in many areas including computer science. The next power of two is 4.

Two is the third member of the Fibonacci sequence (following 1 and preceding 3).

Two is the second factorial number (between 1 and 6), and the first primorial number (next is 6).

2 is the second highly composite number, being the first with 2 or more factors. The next one is 4. It is the only prime highly composite number.

Testing for divisibility by 2 is as simple as checking if the last digit is 0, 2, 4, 6, or 8. If it is, the number is divisible by 2. For instance, 234748 ends in 8 and is a multiple of 2.