Dua juta sudah cukup.

Indonesian often does not use a copula in simple sentences like this.

So where English says:

• Two million is enough

Indonesian can simply say:

• Dua juta cukup

Adding sudah gives the sense of already / now / as it is:

• Dua juta sudah cukup = Two million is already enough / Two million is enough now

So the sentence is normal even without a separate verb meaning is.

Sudah usually means already, but in real usage it often does a bit more than that.

In this sentence, it suggests that the amount has reached a sufficient level. So it can imply things like:

• already enough
• enough now
• sufficient as it is

Compare:

• Dua juta cukup = Two million is enough
• Dua juta sudah cukup = Two million is already enough / Two million should do now

So sudah adds a sense that the requirement has been met.

Because Indonesian often omits nouns that are clear from context.

So dua juta can mean:

• two million rupiah
• two million people
• two million units
• etc.

If the topic is money, most listeners will understand dua juta as something like dua juta rupiah.

If you want to be explicit, you can say:

• Dua juta rupiah sudah cukup.

But if the context already makes it obvious, leaving it out is very natural.

In this sentence, cukup functions like an adjective/predicate adjective, meaning enough or sufficient.

So:

• dua juta = the amount/topic
• sudah cukup = is already enough

Indonesian adjectives can directly act as the predicate without a verb like to be.

You will also see cukup used in other ways, for example:

• cukup besar = quite big / sufficiently big
• cukup = enough
• tidak cukup = not enough

So here, think of it as enough / sufficient.

Indonesian does not work the same way English does with singular/plural agreement.

In English, you might wonder whether to say:

• Two million is enough
• Two million are enough

In Indonesian, that issue does not arise. Dua juta is just the quantity expression, and the predicate does not change form.

So:

• Dua juta sudah cukup

works without any special singular/plural marking.

Yes. Dua juta cukup is grammatical and natural.

The difference is nuance:

• Dua juta cukup = Two million is enough
• Dua juta sudah cukup = Two million is already enough / Two million should be enough now

So sudah adds a sense of the limit being reached or the amount now being sufficient.

Usually, no, or at least it would sound less natural here.

Although both sudah and telah can sometimes correspond to already, telah is more formal and is used more often with verbs than with this kind of everyday adjectival statement.

So:

• Dua juta sudah cukup = natural
• Dua juta telah cukup = possible in a very formal/literary style, but not the normal choice

For everyday Indonesian, sudah is the right word here.

You can add the currency noun:

• Dua juta rupiah sudah cukup.

That is the clearest version if you want to avoid ambiguity.

You could also hear:

• Dua juta aja sudah cukup. = Just two million is already enough.
• Dua juta itu sudah cukup. = That two million is enough.

But if everyone already knows you are talking about money, dua juta sudah cukup is completely normal.

The usual order is:

• topic/subject + sudah + predicate

So:

• Dua juta sudah cukup

is the normal structure.

Putting sudah first in this sentence would sound wrong or very unnatural.

If you want to emphasize the predicate instead, Indonesian might use a different structure, for example:

• Sudah cukup, dua juta.
  This is more like a pause-based spoken style: Two million is enough already.

But as a standard sentence, Dua juta sudah cukup is the best form.

Not by itself. Dua juta sudah cukup simply says that two million is enough.

If you want to emphasize only or just, Indonesian often uses:

• cuma
• hanya
• aja / saja

For example:

• Cuma dua juta sudah cukup.
• Hanya dua juta sudah cukup.
• Dua juta aja sudah cukup.

These more clearly mean:

• Just two million is enough

So the original sentence does not automatically mean only two million, though context might suggest it.

Yes. Cukup can be expanded with phrases like:

• cukup untuk ... = enough for ...
• cukup bagi ... = sufficient for ...

For example:

• Dua juta sudah cukup untuk bayar sewa.
  = Two million is already enough to pay the rent.

• Dua juta sudah cukup bagi kami.
  = Two million is enough for us.

In your sentence, that extra information is simply omitted because the context probably already makes it clear.