twenty billion nine hundred ninety nine million nine hundred ninety nine thousand nine hundred seventy eight Pronunciation in english(IPA) :
ˈtwɛnti ˈbɪljən nʌɪn ˈhʌndrəd ˈnʌɪnti nʌɪn ˈmɪljən nʌɪn ˈhʌndrəd ˈnʌɪnti nʌɪn ˈθaʊz(ə)nd nʌɪn ˈhʌndrəd ˈsɛv(ə)nti eɪt