# Python program to check armstrong number

In this post, we will see how to check if number is Armstrong number.

Armstrong number is a 3 digit number which is equal to sum of cube of its digits.

**For example:** 371,153

Let’s write a simple python program to check armstrong number.

```
def isArmStrong(num):
sum=0;
tempNum=num
while(tempNum!=0):
remainder=tempNum%10
sum+=(remainder**3)
tempNum//=10
if(sum==num):
return True
else:
return False
# Testing the function
print("Is 371 armstrong number : ",isArmStrong(371))
print("Is 134 armstrong number : ",isArmStrong(134))
print("Is 134 armstrong number : ",isArmStrong(153))
```

**Output:**

Is 371 armstrong number : True

Is 134 armstrong number : False

Is 134 armstrong number : True

Is 134 armstrong number : False

Is 134 armstrong number : True

Let’s understand the program.

- Initialize sum with 0
- Iterate over while loop and find the remainder
- calculate cube of remainder and Add to the sum. If you look closely we are actually adding cube of each digit
**tempNum//=10**-> With this step, we are removing most less significant digit in each iteration

That’s all about Python program to find armstrong number.