number cruncher vs calculator

number cruncher and calculator both are nouns.

Word	Noun	Adjective	Verb	Adverb
number cruncher	Yes	No	No	No
calculator	Yes	No	No	No

As nouns, calculator is a hypernym of number cruncher; that is, calculator is a word with a broader meaning than number cruncher:

Other hypernyms of number cruncher include computer, estimator, figurer, reckoner.

number cruncher (noun)	calculator (noun)
a computer capable of performing a large number of mathematical operations per second	a small machine that is used for mathematical calculations; can be mechanical or electronic
someone able to perform complex and lengthy calculations	an expert at calculation (or at operating calculating machines)