为什么以下程序在必须处理某些值时会停止工作？

Question

当“ num”值达到31或61或67等时，程序就停止工作（通过手动更改num值找到这些数字）

temp_total = 0
num = 1

while True:
    print(num)
    check = (2**num)-1
    for r in range(1, check+1):
        if check!=1 and r!=1 and r!=check:
            if check%r == 0:
                temp_total += 1
                break
    if temp_total == 0 and check != 1:
        print('\n\nThe value of n in the equation is ', num)
        print('The prime number is ', check)
        calculate = (2**(num-1))*((2**num)-1)
        print('The perfect number is ', calculate, '\n\n\n')   

    temp_total = 0
    num += 1

我希望程序能够连续运行，而不是在'num'达到随机值时停止运行。