I tried to figure out what does total number of blocks per day means here and on the Internet, but i failed. For example, the number of blocks on 26 Aug is 5947 [here https://etherscan.io/chart/blocks]. My question is whether this number includes main blocks (that made it to the main ethereum blockchain) + uncle and stale blocks? or just the main blocks?
I made some calculations e.g., if 5947 is only main blocks, uncles is 1044 [here https://etherscan.io/chart/uncles], which result in 6991 blocks produced on 26 Aug. This contradict with average block time, which is 14.21 s [here https://etherscan.io/chart/blocktime] as the number of blocks per day should be 86400/14.21= 6080 blocks.
If 5947 includes uncles and stales, this is close to the expected 6080 blocks, but still there is a difference as the average block time should be 86400/5947= 14.53 seconds.
hence 1 day = 86400 seconds