Adobe has released 64 bit version of Acrobat Reader for Linux
To install in ubuntu,open terminal and type
sudo apt-get install acroread
Or Visit
http://www.adobe.com/products/reader.html
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Adobe has not released 64bit Acrobat reader for Linux and its not possible to install 32bit acrobat reader without doing some tweaks on 64bit Linux. so solution is to install i486 version of Acrobat reader.
Its Available for download at http://www.adobe.com/support/downloads/thankyou.jsp?ftpID=4454&fileID=4162
After you download the AdbeRdr9.4.2-1_i486linux_enu.bin file
open terminal and cd to the directory where you have saved the installation file
Now type sudo chmod a+x AdbeRdr9.4.2-1_i486linux_enu.bin
And Then type sudo ./AdbeRdr9.4.2-1_i486linux_enu.bin
This should install Acrobat reader on your 64bit Linux Os
For other Versions of Acrobat reader for Linux And Solaris
Visit
http://www.adobe.com/support/downloads/product.jsp?product=10&platform=unix