🚀 Day 38/150 – Prime Number Check in Python

A Prime Number is a number greater than 1 that has only two factors: 1 and itself.

Examples:
2, 3, 5, 7, 11 → Prime Numbers
4, 6, 8, 9 → Not Prime Numbers

Let’s explore different ways to check prime number in Python 👇

🔹 Method 1 – Using for Loop

n = 7 is_prime = True if n <= 1: is_prime = False else: for i in range(2, n): if n % i == 0: is_prime = False break print("Prime Number" if is_prime else "Not Prime Number")

Simple beginner-friendly method.

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🔹 Method 2 – Taking User Input

n = int(input("Enter a number: "))
is_prime = True

if n <= 1:
    is_prime = False
else:
    for i in range(2, n):
        if n % i == 0:
            is_prime = False
            break

print("Prime Number" if is_prime else "Not Prime Number")

Useful when you want to test different numbers.

🔹 Method 3 – Optimized Using √n

n = 29
is_prime = True

if n <= 1:
    is_prime = False
else:
    for i in range(2, int(n ** 0.5) + 1):
        if n % i == 0:
            is_prime = False
            break

print("Prime Number" if is_prime else "Not Prime Number")

 More efficient because factors repeat after the square root.

🔹 Method 4 – Using while Loop

n = 13 i = 2 is_prime = True if n <= 1: is_prime = False else: while i < n: if n % i == 0: is_prime = False break i += 1 print("Prime Number" if is_prime else "Not Prime Number")

Same logic, just using a different loop.

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💡 Key Takeaways

1)Prime numbers have exactly two factors
2)Numbers less than or equal to 1 are not prime
3)Checking up to √n is faster than checking all numbers
4)The optimized method is better for larger values