Write a natural number A, add the tens digit and hundreds digit of A, multiply by the unit digit, and write the unit digit of the product at the end of A, which is called an operation. If A=2894 at the beginning, perform one operation on 2894 to obtain 28948, and then perform one operation on 28948 to obtain 289484, and so on until a 2894-digit number is obtained, what is the sum of the digits of this 2894-digit number?
写出一个自然数A，把A的十位数字与百位数字相加，再乘以个位数字，把所得的积的个位数字续写在A的末尾，称作一次操作．如果开始时A=2894，对2894进行一次操作得到28948，再对28948进行一次操作得到289484，如此进行下去，直到得出一个2894位数为止，这个2894位数的各位数字之和是多少．
<gadget id="calculator">2 + 8 + 9 + 4 + 8 + 4 + 8 + 6 + 2 + 8 + 4</gadget>
<output>63</output>

<result>63</result>