Here under Python 3.8.1 on 64-bit Windows:

>>> import decimal
>>> c = decimal.getcontext()
>>> c.prec = decimal.MAX_PREC
>>> i = decimal.Decimal(4)
>>> i / 2
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
MemoryError

Of course the result is exactly 2.  Which I have enough RAM to hold ;-)

The implicit conversion is irrelevant:

>>> i / decimal.Decimal(2)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
MemoryError

Floor division instead works fine:

>>> i // 2
Decimal('2')