septillion

1 million has 6 zeros (1,000,000); 1 billion has 9 zeros (1,000,000,000); 1 trillion has 12 zeros (1,000,000,000,000); 1 quadrillion has 15 zeros; 1 quintillion has 18 zeros; 1 sextillion has 21 zeros; 1 septillion has 24 zeros