def is_prime(n):
    if n <= 1:
        return False
    elif n <= 3:
        return True
    elif n % 2 == 0 or n % 3 == 0:
        return False
    i = 5
    while i * i <= n:
        if n % i == 0 or n % (i + 2) == 0:
            return False
        i += 6
    return True

def find_primes():
    primes = []
    for num in range(500, 600):
        if str(num)[0] == '5' and is_prime(num):
            primes.append(num)
    return primes

print("Prime numbers starting with 5 and having 3 digits:")
print(find_primes())