A positive integer greater than 1 which has no other factors except 1 and the number itself is called a prime number.

2, 3, 5, 7 etc. are prime numbers as they do not have any other factors. But 6 is not prime (it is composite) since, `2 x 3 = 6`

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## Source Code

```
# Python program to display all the prime numbers within an interval
lower = 900
upper = 1000
print("Prime numbers between", lower, "and", upper, "are:")
for num in range(lower, upper + 1):
# all prime numbers are greater than 1
if num > 1:
for i in range(2, num):
if (num % i) == 0:
break
else:
print(num)
```

**Output**

Prime numbers between 900 and 1000 are: 907 911 919 929 937 941 947 953 967 971 977 983 991 997

Here, we store the interval as `lower` for lower interval and `upper` for upper interval, and find prime numbers in that range. Visit this page to learn how to check whether a number is prime or not.