Problem
https://projecteuler.net/problem=16
\(2^{15} = 32768\) and the sum of its digits is \(3 + 2 + 7 + 6 + 8 = 26\).
What is the sum of the digits of the number \(2^{1000}\)?
Answer: 1366
Solution
#!/usr/bin/env ruby
def power_digit_sum(power)
digits = (2**power).to_s
digits.split('').reduce(0) { |sum, digit| sum + digit.to_i }
end
puts power_digit_sum(1000) if __FILE__ == $PROGRAM_NAME