1. 0770 = 770 octal
2. 770 = 770 decimal (weird bits)
3. "0770" = 770 decimal
4. "770" = 770 decimal
5. "1770" = 1770 decimal (different weird bits)
6. 1770 = 1770 decimal

And as someone else already said, yes, the bits of the umask are cleared from this value. Either change your umask, or try a chmod afterward.

-- Randal L. Schwartz, Perl hacker