Hindu Arabic numerals are the ones we use. 39 is already in Hindu-Arabic numerals.
In today's terms: XXXIX = 39
In today's terms: XXXIX
VII-XXXIX-MMX
XXXIX is the equivalent of 39 in the Roman Numerals.
In todays modern usage of Roman numerals it is: XXXIX But the ancient Romans probably worked it out quite differently
39 in Roman numerals is XXXIX
XXXIX
The formula =ARABIC(IXL) in MS Excel returns 39. So too, does =ARABIC(XXXIX), Over the centuries usage of Roman numerals has varied with the users and the space available to chisel it. Compare vintage and modern clockfaces.
XXXIX
39
In today's terms the above numerals represent 39
A satisfactory explanation can be given that 39600000 transposed into Roman numerals is probably (XXXVIIII)M(DC) indicating 39*1000*1000+600*1000 = 39 600 000.