how to convert dict_values into a set

I have a dict that contains sets as values for each key, e.g.

{'key1': {8772, 9605},'key2': {10867, 10911, 10917},'key3': {11749,11750},'key4': {14721, 19755, 21281}}

Now I want to put each value, i.e. set of ints into a set, I am wondering what is the best way/most efficient way to do this.

{8772,9605,10867,10911,10917,11749,11750,14721,19755,21281}

I tried to retrieve the values from the dict using dict.values(), but that returns a dict_values object, making it a list, list(dict.values()) gave me a list of sets, set(list(exact_dups.values())) threw me errors,

TypeError: unhashable type: 'set'

UPDATE. forgot to mention the result set also need to maintain uniqueness, i.e. no duplicates.