Prime numbers not divisible by 2 are all prime numbers except the number 2 itself.
Here's a breakdown:
Understanding Prime Numbers
A prime number is a whole number greater than 1 that has only two divisors: 1 and itself. Examples of prime numbers include 2, 3, 5, 7, 11, and so on.
Prime Numbers and Divisibility by 2
- Divisible by 2: A number is divisible by 2 if it is an even number. All even numbers (e.g., 2, 4, 6, 8...) are divisible by 2.
- The Number 2: The number 2 is the only even prime number. This means that all other prime numbers must be odd.
Prime Numbers Not Divisible by 2
Therefore, all prime numbers, except for 2, are not divisible by 2. These numbers include:
- 3
- 5
- 7
- 11
- 13
- 17
- 19
- 23
- and so on
Analyzing the Reference
The reference states, "Since 2, 3, 5 and 7 are prime numbers, total prime numbers, which are not divisible by 2, 3, 5 and 7, are (25 - 4) 21." This statement helps to understand how many prime numbers are not divisible by multiple given numbers.
Here is a table summarising the key point:
| Divisor | Prime Numbers Divisible by the Divisor | Prime Numbers NOT Divisible by the Divisor |
|---|---|---|
| 2 | 2 | 3, 5, 7, 11, 13, ... |
| 3 | 3 | 2, 5, 7, 11, 13,... |
| 5 | 5 | 2, 3, 7, 11, 13, ... |
| 7 | 7 | 2, 3, 5, 11, 13,... |
The reference focuses on calculating prime numbers not divisible by 2, 3, 5, and 7. This helps illustrate the concept that all prime numbers, except for 2, are not divisible by 2.
Conclusion
In summary, all prime numbers other than 2 are not divisible by 2. They are odd numbers with only two factors: 1 and themselves.
