<?xml version="1.0" encoding="windows-1251"?>
<xsl:stylesheet version="1.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  
  <xsl:decimal-format grouping-separator=' '/>

  <xsl:template match="/">
    <val>
      <xsl:value-of select="format-number(1234567890, '### ### ### ###')"/>
    </val>
  </xsl:template>
</xsl:stylesheet>

<xsl:value-of select="format-number(1234567890, '### ### ### ##0')"/>