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1. Count Digits in a Number2. Reverse a Number3. Check Palindrome Number4. Sum of Digits5. Armstrong Number Check6. Perfect Number Check7. Print Primes Between 1-1008. Check if Number is Prime9. Fibonacci Series Up to N10. Sum of First N Fibonacci Terms11. Product of Digits12. Strong Number Check13. Harshad Number Check14. Abundant Number Check

Check if Number is Prime

Check if a number is prime.

IntermediatePhase 2 - Level 2: Number-based Looping LogicExample 8 of 14
check-if-number-is-prime.py
1# Take number
2num = int(input("Enter a number: "))
3

4# Check prime
5if num < 2:
6    print("Not prime")
7else:
8    is_prime = True
9    for i in range(2, int(num ** 0.5) + 1):
10        if num % i == 0:
11            is_prime = False
12            break
13    
14    if is_prime:
15        print("Prime")
16    else:
17        print("Not prime")

Output

Enter a number: 17
Prime

Enter a number: 15
Not prime

What's going on

Check if number has any divisors.

Key Concepts:

Numbers < 2 are not prime
Check divisors from 2 to sqrt(num)
If any divisor found, not prime

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