Check whether a number can be expressed as a sum of two prime numbers In Python

               

    Check whether a number can be expressed as a sum of two prime numbers In Python

For example, the number 34 is given as input.

34 = 3 + 31
34 = 5 + 29
34 = 11 + 23
34 = 17 + 17

Program:

# Python program to check whether a number can be expressed as a sum of two prime numbers

def prime(n):

    isPrime = 1

    for i in range (2,int(n/2),1):

        if(n % i == 0):

            isPrime = 0

            break

    return isPrime

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

f = 0;

i = 2

for i in range (2,int(n/2),1):

    if(prime(i) == 1):

        if(prime(n-i) == 1):

            print(n,"can be expressed as the sum of",i,"and",n-i)

            f = 1;

if (f == 0):

    print(n,"cannot be expressed as the sum of two prime numbers")

OutPut:

Enter a number : 34

34 can be expressed as the sum of 3 and 31

34 can be expressed as the sum of 5 and 29

34 can be expressed as the sum of 11 and 23

Enter a number : 35

35 can be expressed as the sum of 4 and 31

Enter a number : 37

37 cannot be expressed as the sum of two prime numbers

replace all 0's with 1 in a given integer In Python

              

        Replace all 0's with 1 in a given integer In Python

Input: 102405
Output: 112415

Program:

# Python program to replace all 0’s with 1 in a given integer

def re(n):

    if (n == 0):

        return 0;

# Extract the last digit and change it if needed

    digit = n % 10

    if (digit == 0):

        digit = 1

    return re(int(n/10)) * 10 + digit

n = int(input("Enter the number : "))

print("Number after replacement : ",re(n))

OutPut:

Enter the number : 123034

Number after replacement :  123134

Python program to print the Armstrong numbers between the two intervals

             

        Python program to print the Armstrong numbers between the two intervals

An Armstrong number of three digits is an integer such that the sum of the cubes of its digits is equal to the number itself. For example, 153  is an Armstrong

Program:

# Python program to print the Armstrong numbers between the two intervals

import math

n1 = int(input("Enter start value : "))

n2 = int(input("Enter end value : "))

result = 0

n = 0

for i in range(n1+1 ,n2,1):

    t2 = i

    t1 = i

    while (t1 != 0):

        t1 = int(t1/10)

        n = n + 1

    while (t2 != 0):

        remainder = t2 % 10

        result = result + math.pow(remainder, n)

        t2 = int(t2/10)

    if (result == i):

        print(i)

    n = 0

    result = 0

OutPut:

Enter start value : 100

Enter end value : 500

153

370

371

407

Enter start value : 200

Enter end value : 1000

370

371

407

Prime Number Program in Given Range in Python

  

         Prime Number Program in Given Range in Python

Prime number in C: Prime number is a number that is greater than 1 and divided by 1 or itself. In other words, prime numbers can't be divided by other numbers than itself or 1. For example 2, 3, 5, 7, 11, 13, 17, 19, 23.... are the prime numbers.

factors Program In Python

            

        Factors Program In Python

the factors of number 10 are
1 * 10 = 10
2 * 5 = 10
5* 2 = 10
10* 1 = 10

Program:

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

count = 0

for i in range(1, n+1, 1):

    if(n % i == 0):

        count = count + 1

        print(i, end = " ")

print("\nTotal factors of",n," is :",count)

OutPut:

Enter a number : 10

1 2 5 10 

Total factors of 10 : 4

Enter a number : 20

1 2 4 5 10 20 

Total factors of 20  is : 6

Abundant number In Python

           

        Abundant number In Python

An abundant number is a number for which the sum of its proper divisors is greater than the
 number itself.
The divisors of 12 are 1, 2, 3, 4 and 6.
The sum of divisors of 12 is 16.
12 < 16.Hence, 12 is an abundant number.

Program:

n = int(input("Enter N Value"))

sum = 0

for i in range(1,n):

if(n % i == 0):

sum = sum + i

if(n < sum):

print("It is a Abundant Number")

else:

print("Not Abundant Number")

OutPut:

Enter N Value12

It is a Abundant Number

Enter N Value4

Not Abundant Number

Harshad number In Python

          

        Harshad number In Python

Harshad Number is an integer that is divisible by the sum of its digits.

Program:

n = int(input("Enter Number"))

sum = 0

temp = n

while(temp > 0):

sum += temp % 10

temp = int(temp // 10)

res = n % sum

if(res == 0):

print("Harshad Number");

else:

print("Not Harshad Number");

OutPut:

Enter Number1729

Harshad Number

Enter Number1930

Not Harshad Number

Automorphic Number In Given Range In Python

         

        Automorphic Number In Given Range In Python

An automorphic number is a number whose square ends in the same digits as the 
original number itself. Examples: 5, 76, etc.

Program:

def isAutomorphic(num):

  #square of the number

  sqr = num**2

  #number of digits in num 

  n = len(str(num))

  #last n digits of the square

  last = sqr%pow(10,n)

  return last == num

n1=int(input("Enter Starting Value"))

n2=int(input("Enter Ending Value")) 

#loop through all the numbers in the range

for x in range(n1,n2):

  if isAutomorphic(x):

    print(x,end=' ')

OutPut:

Enter Starting Value1

Enter Ending Value100

1 5 6 25 76 

check whether the given number is Automorphic or not In Python

        

         check whether the given number is Automorphic or not.

 In Python

An automorphic number is a number whose square ends in the same digits as the 
original number itself. Examples: 5, 76, etc.

Program:

num = int(input("Enter a number:"))

#find number of digits in num 

n = len(str(num))

#compute square

sqr = num**2

#Extract last n digits from the square

last = sqr%pow(10,n)

#compare last n digits with the input number

if last == num:

  print("Automorphic Number")

else:

  print("Not an Automorphic Number")

OutPut:

Enter a number: 

5

Automorphic Number

Enter a number:25

Automorphic Number

Enter a number:26

Not an Automorphic Number

find if the given numbers are Friendly pair or not In Python

       

        find if the given numbers are Friendly pair or not 

 In Python

For example,6 and 28 are Friendly Pair.
(Sum of divisors of 6)/6 = (Sum of divisors of 28)/28.

Program:

n1 = int(input("Enter First Number"))

n2 = int(input("Enter Second Number"))

s1 = 0

s2 = 0

for i in range(1,n1):

if(n1 % i == 0):

s1 = s1 + i

for i in range(1,n2):

if(n2 % i == 0):

s2 = s2 + i

if(s1 == n1 and s2 == n2):

print("Friendly Pair")

else:

print("Not Friendly Pair")

OutPut:

Enter First Number6

Enter Second Number28

Friendly Pair

Enter First Number6

Enter Second Number24

Not Friendly Pair

Perfect number Program In Python

      

         Check whether a given number is perfect number or not

 In Python

Program to check whether a given number is a perfect number or not is discussed here. A perfect number is a number which is equal to the sum of its proper positive divisors.

For example, 6 is a perfect number.
The divisors of 6 are 1, 2 and 3.
1 + 2 + 3 = 6.

Program:

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

sum = 0

for i in range (1,n):

    if(n % i == 0):

        sum = sum + i

if(sum == n):

    print(n,"is a perfect number")

else:

    print(n,"is not a perfect number")

OutPut:

Enter a number : 6

6 is a perfect number

Enter a number : 123

123 is not a perfect number

Find the sum of numbers in a given range In Python

     

         Find the sum of numbers in a given range In Python

Program:

startnum = int(input("Enter Start Number" ))

endnum = int(input("Enter Ending Number"))

sum = 0

for i in range(startnum, endnum + 1, 1):

sum = sum + i

print(sum)

OutPut:

Enter Start Number1

Enter Ending Number10

55

Enter Start Number20

Enter Ending Number30

275

Find Number of digits in Given Number In Python

    

Find Number of digits in Given Number  In Python 

Program:

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

count = 0

while(n != 0):

    n = int(n/10)

    count = count + 1

print("Number of digits in Given Number is :",count)

OutPut:

Enter a number : 1224

Number of digits in Given Number is : 4