Colors and Numbers

Are colors and numbers things? We use them as nouns, but are they really nouns or just adjectives that function like nouns? Things are red or a group of objects has the property of having four members, but we treat red and four as if they have independent existence. Do they?

With numbers, we attribute properties and relations among them. That seems to be good reason to think them things. But what kind of things?

Is the same true of colors? We do label some primary and other secondary or tertiary. Does this bring colors on par with numbers?