A leading zero in literal indicates the number is octal.

22000 = 2*10⁵ + 2*10⁴
022000 = 2*8⁵ + 2*8⁴

That rule doesn't apply for string numification.

0+'22000' = 2*10⁵ + 2*10⁴
0+'022000' = 2*10⁵ + 2*10⁴
oct('22000') = 2*8⁵ + 2*8⁴
oct('022000') = 2*8⁵ + 2*8⁴