An "Armstrong number" is an n-digit number that is equal to the sum of the nth powers of its individual digits. For example, 153 is an Armstrong number because it has 3 digits and 13+53+33=153. What is the digit k in the Armstrong number 1,6k4?
2
3
4
5
6
为了时间问题,只考虑尾数即可,4的4次方位数是6 6的正整数次方,位数都是6,1的尾数是1,加起来是13,所以K的4次方要以1结尾。(我不相信自己,就拼命算了好几遍,选项里就是没有1)3的4次方=81
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