LibreOffice and OpenOffice's spreadsheet, and the ISO-standard one - the same ODF packaging an ODT uses, with sheets where a document has pages. Every cell stores its value and, separately, the text shown for it, which is why a figure formatted as currency can still be read back as the number underneath.
Every conversion below runs in this page, on your own machine. Nothing is uploaded, there is no queue, and there is no account to make. Pick a target format, or just drop an ODS file above and choose afterwards.