Meaning of plus sign, backslash and semicolon as arguments in find command

Hi everyone,
I am sure most of us have come across this command which looks for files with 777 permissions and deletes them:

find -type f -perm 0777 -exec rm -i {} +;

I know that {} is a placeholder for the files that are returned by the command, but the question is, what does the plus sign and the semicolon at the end of the command mean?
Another variation of the same command is:

find -type f -perm 0777 -exec rm -i {} \;

where the plus sign is replaced by a backslash.
Thanks in advance.

I think backslash will assign each file to be executed one by one like this:
rm -i file1
rm -i file2
rm -i file3

and + sign at the end assigns all files found as parameters to a single command:
rm -i file1 file2 file3

Someone correct me if i’m wrong.

";" is used for shell to determine end of command
for example:

echo hello ; date ; cal

when you use “” you says to shell don’t interpret ";"
"" means escape character and shell does not interpret character after ""
"+" and " ;" terminates exec command inside of find