Erlang solution for Euler problem 16

In project Euler problem number 16 we are asked to sum the digits of the number 2^1000.

The Erlang solution for this one is trivial, thanks to the arbitrary precision integer support in Erlang:

%% Project Euler, problem 16
%% 
%% What is the sum of the digits of the number 2^1000?

-module(euler16).
-author('Cayle Spandon').

-export([solve/0, solve/1]).

power_of_2(N) ->
    1 bsl N.

digits_sum(N) ->
    if 
        N < 10 ->
            N;
        true ->
            (N rem 10) + digits_sum(N div 10)
    end.

solve() ->
    solve(1000).

solve(N) ->
    digits_sum(power_of_2(N)).