Number:2 (Meta, no ontology)
From Compile Worlds
(Created page with '{{fact}} '''Two''' is the smallest prime number. An integer is called even if it is divisible by 2. For integers written in a numeral system based on an even number, such as...') |
m |
||
| (3 intermediate revisions not shown) | |||
| Line 1: | Line 1: | ||
| - | |||
| - | |||
'''Two''' is the smallest [[prime number]]. An integer is called even if it is divisible by 2. For integers written in a numeral system based on an even number, such as decimal and hexadecimal, divisibility by 2 is easily tested by merely looking at the one's place digit. If it is even, then the whole number is even. In particular, when written in the decimal system, all multiples of 2 will end in 0, 2, 4, 6, or 8. | '''Two''' is the smallest [[prime number]]. An integer is called even if it is divisible by 2. For integers written in a numeral system based on an even number, such as decimal and hexadecimal, divisibility by 2 is easily tested by merely looking at the one's place digit. If it is even, then the whole number is even. In particular, when written in the decimal system, all multiples of 2 will end in 0, 2, 4, 6, or 8. | ||
Latest revision as of 13:32, 3 February 2011
Two is the smallest prime number. An integer is called even if it is divisible by 2. For integers written in a numeral system based on an even number, such as decimal and hexadecimal, divisibility by 2 is easily tested by merely looking at the one's place digit. If it is even, then the whole number is even. In particular, when written in the decimal system, all multiples of 2 will end in 0, 2, 4, 6, or 8.
Despite being a prime, two is also a highly composite number, because it has more divisors than the number one. The next highly composite number is four. Two and three are the only two consecutive prime numbers. Two is the first Sophie Germain prime, the first factorial prime, the first Lucas prime, and the first Smarandache-Wellin prime. It is an Eisenstein prime with no imaginary part and real part of the form 3n − 1. It is also a Stern prime, a Pell number, and a Markov number. It is the third Fibonacci number, and the third and fifth Perrin numbers.
Two is the base of the simplest numeral system in which natural numbers can be written concisely (binary), being the length of the number a logarithm of the value of the number (whereas in base 1 the length of the number is the value of the number itself); the binary system is used in computers.
