Count of the digits of a number in Java public class Main { public static void main(String[] args) { int number = -123456; if(number < 0) number = -number; int count = number == 0 ? 1 : 0; while (number > 0) { number /= 10; count++; } System.out.println(sum); } } Time Complexity: O(log₁₀N) ; N is the number. Space Complexity: O(1).