The SDK size on iOS and Android is approximately 6MB and 2MB respectively.
The memory usage of the SDK is a bit complicated, as it is affected by device’s display quality and also the host game. Here is the general figure and the the factors involved:
iOS 60-80 MB
Android 30-50 MB
Factors: During the SDK initialization stage before the community is invoked, it will only take up a minor amount of memory. After the community UI is opened, more memory will be used particularly when media files like images and media resources are involved, but then memory is released as soon as you leave the page.
When the community is closed, the memory used by the community UI will be released (and return to minimal as it was in the initialization stage)