99999...11111 (30-digits)

This number is a composite.

                                            9999997777 7755555533 3333111111

The integer 999999777777555555333333111111, made entirely from nonascending odd digits, factors into primes made entirely from odd digits: 999999 777777 555555 333333 111111 = 3 x 7 x 11 x 13 x 37 x 9000007000005000003000001. [Post]