99999...11111 (60-digits)

This number is a composite.

           9999999999 9977777777 7777555555 5555553333 3333333311 1111111111

The integer 999999 999999 777777 777777 555555 555555 333333 333333 111111 111111, made entirely from a dozen each nonascending odd digits, factors into integers made entirely from odd digits: = 3 x 7 x 11 x 13 x 37 x 101 x 9901 x 9000000000007000000000005000000000003000000000001. Note that the longest factor is semiprime, whose prime factors have exactly half a dozen plus one even digits in the first and a baker's dozen even digits in the second: 4059109143676057 x 2217235280314812310553388323553193. [Post]