Azure Table Exception: One of the request inputs is not valid

When trying to insert data into an Azure Table, and calling SaveChanges() you may get an exception like:

One reason that you can get this error is if you are trying to insert an unsupported type into a table.  Decimal types, for example, are unsupported at this time.

The list of supported types are:

ADO.NET Data Services type	Common Language Runtime type	Details
Edm.Binary	byte[]	An array of bytes up to 64 KB in size.
Edm.Boolean	bool	A Boolean value.
Edm.DateTime	DateTime	A 64-bit value expressed as Coordinated Universal Time (UTC). The supported DateTime range begins from 12:00 midnight, January 1, 1601 A.D. (C.E.), UTC. The range ends at December 31, 9999.
Edm.Double	double	A 64-bit floating point value.
Edm.Guid	Guid	A 128-bit globally unique identifier.
Edm.Int32	Int32 or int	A 32-bit integer.
Edm.Int64	Int64 or long	A 64-bit integer.
Edm.String	String	A UTF-16-encoded value. String values may be up to 64 KB in size.

This list is from: https://msdn.microsoft.com/en-us/library/dd179338.aspx