Number Properties

NUMBER PROPERTIES

Property 1:         2 is the only even prime number. So, every prime number other than 2 is an odd number.

Property 2:         Every odd number is not a prime number.

Property 3:         Number 1 is neither prime nor composite as it has only 1 factor that is 1.

Property 4:         Every even number greater that 4 can be expressed as the sum of two odd prime numbers.

Property 4:         Every even number greater that 4 can be expressed as the sum of two odd prime numbers.

Property 5:         Prime numbers occurring in pairs with a difference of 2 are called TWIN PRIME numbers.

Pair of Twin-primes:

3,5: 5,7: 11,13: 17,19: 29,31: 41,43: 59,61 and 71,73.

Property 6:         A set of 3 consecutive prime numbers, differing by 2, is called a PRIME-TRIPLET.

The only prime-triplet is 3,5,7.

Property 7:         Two numbers are called CO-PRIME if they do not have any factor in common other than 1.

2,3: 3,4: 5,6: etc

Property 8:         If the sum of all the factors of a number is twice the number, then the number is called Perfect Number.

Example: Number 6

Factors are: 1,2,3,6

Sum of the factors: 1+2+3+6= 12

Twice the Number = 2*Number=2*6=12

So, Sum = Twice the Number

Hence 6 is the perfect Number.

Property 9:         If P and Q are the prime factors of number A, then their product is also a factor of number A.

Example: 2,5 are prime factors of 30, so 2*5=10 is also a factor of number 30.