The long data type is derived from the integer type. : long « XML Schema « XML Tutorial

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The value space is integer values from 9223372036854775808 up to and including 9223372036854775807. 
The lexical space is a finite-length sequence of decimal digits with an optional leading - or +.

<!-- schema -->
<xsd:element name="bignumbers">
<xsd:simpleType>
  <xsd:restriction base="xsd:long">
   <xsd:enumeration value="2177483647"/>
   <xsd:enumeration value="-2177483647"/>
  </xsd:restriction>
</xsd:simpleType>
</xsd:element>
<!-- instance document -->
<bignumbers>2177483647</bignumbers>