What is the digital root (repeated sum of digits) of 987654?

Explanation

9+8+7+6+5+4 = 39. 3+9 = 12. 1+2 = 3. Wait: 987654 → 39 → 12 → 3. The answer is 3, but checking: 987654/9 has remainder 0 (as 9+8+7+6+5+4=39, 3+9=12, 1+2=3). Actually digital root is 3.