What is 50000000000.00 in words?

5 with 12 zero's is five trillion, in short scale countries, such as the US, specifically, most English speaking countries. In long scale countries, such as previously the UK (up to 1974), but still in some residual use there, as well as currently in other countries, specifically most European origin countries, it is five billion. See the Related Link below for more information.

To be unambiguous, one should use scientific notation, 5 x 1012, or the SI prefix, tera-, when speaking of this large number.