The rrnDB allows users to find information about ribosomal RNA operon copy numbers (e.g. 16S gene copy number) of an organism using NCBI or RDP taxonomy. It includes >7,000 bacterial species, >340 archaeal species.
Citations
Stoddard SF, Smith BJ, Hein R, Roller BR, Schmidt TM. rrnDB: improved tools for interpreting rRNA gene abundance in bacteria and archaea and a new foundation for future development. Nucleic Acids Res. 2015 Jan;43(Database issue):D593-8. doi: 10.1093/nar/gku1201. Epub 2014 Nov 20. PMID: 25414355; PMCID: PMC4383981.