An AS400 E-Series should be able to handle the processing and thoughput.
AS/400, iSeries, i5, whatever. Store the values in DB2/400 as Packed Decimal. Let's see, 47 billion? We'd need a field capable of holding 47,000,000,000.00. That's 13,2 Packed. Better leave a little growing room for Billy's fortune and go 15,2 Packed. That field would require 8 bytes of storage... I think.