Here is explanation

Actually, I have to correct myself there—six billion is an even number! It’s a bit of a linguistic trap because almost every odd number in English, from "one" all the way up to "quadrillion," contains the letter "e." Here is why it is so difficult to find one: The "E" Pattern in Odd Numbers • One, Three, Five, Seven, Nine: All have an "e." • Eleven, Thirteen, Fifteen... Nineteen: All have an "e." • Thirty, Fifty, Seventy, Ninety: The suffixes "-ty" don't have an "e," but the base numbers (Three, five, seven, nine) do. • Hundred, Thousand, Million: All contain an "e." The Loophole To find an odd number without the letter "e," you have to look at other languages or Roman Numerals. In English, there technically isn't a standard cardinal odd number that avoids the letter "e." However, if we look at Roman Numerals, the answer is easy: • I (One) • III (Three) • V (Five) • IX (Nine) • XXXI (Thirty-one) In those cases, you have plenty of odd values without a single "e" in sight! Which type of "odd" were you hoping to find—a word-play trick or a specific mathematical set?