There are many, many more odd prime numbers than even prime numbers; there is only 1 even prime number, namely 2, whereas the odd prime numbers are 3, 5, 7, 11, ...
Odd. There is only 1 prime number in the even group: 2. This is because all even numbers above 2 have at least three factors: 1, 2, and itself. There are many odd prime numbers: 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 41, 43, 47, 53, 59...
2, 3, 5, and 9 includes one composite number - 9. 3, 11, 23, and 31 are all prime numbers. 2, 5, 15, and 19 includes one composite number - 19. 7, 17, 29, and 49 includes one composite number - 49.
Any two prime numbers will be relatively prime. Numbers are relatively prime if they do not have any prime factors in common. Prime numbers have only themselves as prime factors, so all prime numbers are relatively prime to the others.
You know that the odd digits have to be in the units places, and the evens in the tens place, so the general solution is: 80 + 60 + 40 + 20 + 9 + 7 + 3 + 1 = 220
Odds
odds
odds
Because evens can always be divided by 2
There are many, many more odd prime numbers than even prime numbers; there is only 1 even prime number, namely 2, whereas the odd prime numbers are 3, 5, 7, 11, ...
odd numbers
NOTHING!
3112331 and 251519 are prime.
3112331
Prime factorization never includes a composite number. All numbers in prime factorization must be prime numbers.
1 to 50
The factors of 30 and 60 include the prime numbers 2, 3, and 5.