Only one prime number less than 1000 is divisible by 7.
Understanding Prime Numbers and Divisibility
A prime number is a whole number greater than 1 that has only two divisors: 1 and itself. The number 7 is a prime number. Any multiple of 7 (other than 7 itself) will have at least three divisors (1, 7, and the multiple itself), therefore, it cannot be prime.
- Example: 14 (7 x 2) is divisible by 1, 2, 7, and 14. It's not prime.
- Example: 21 (7 x 3) is divisible by 1, 3, 7, and 21. It's not prime.
The only prime number divisible by 7 is 7 itself. All other multiples of 7 are composite numbers (numbers with more than two divisors). Since we are considering numbers less than 1000, only the number 7 fits this criteria.
This is consistent with information found in several sources:
- One source explicitly states, "We can only get one prime number which is equal to seven that is divisible by one and seven and hence is a prime number."
- Another source confirms, "Only one prime number that is 7 below 1000 is divisible. All other multiples of 7 are no longer prime numbers."
Therefore, there is only one prime number less than 1000 that is divisible by 7.
