Saint Helena has the international calling code +<answer>2</answer>90 which, since <answer>2</answer>006, Tristan da Cunha shares. Saint Helena telephone numbers changed from 4 to 5 digits on 1 October <answer>2</answer>013 by being prefixed with the digit "<answer>2</answer>", i.e. <answer>2</answer>xxxx, with the range 5xxxx being reserved for mobile numbering, and 8xxx being used for Tristan da Cunha numbers (these still shown as 4 digits).
What digit are Saint Helena phone numbers prefixed with?
2