The rising prevalence of people possessing ever increasing quantities of wealth has given rise to additional terms to further differentiate millionaires. Individuals with net assets of 100 million or more of a currency are commonly termed centimillionaires,[22] or more rarely hectomillionaires.[23]
Nope, both work, but centimillionaire is more common, so I use that.
https://en.wikipedia.org/wiki/Millionaire#Multimillionaire