99939

Appears in sequences

• Numbers having four 9's in base 10.at n=30A043528
• a(n) = largest composite number of n decimal digits that becomes prime by decreasing any one of the higher-order digits.at n=3A124113
• Absolute discriminants of complex quadratic fields with 3-class group of type (3,3) and 3-principalization type (2241).at n=45A247689