8900 is the martian number
426100
Because
Given a decimal number X, we can represent it in quotient form X=8*Q+RX=4*Q+R. The first part of the martian number (all but the last two numbers) is Q octal, and the last two numbers are R in binary.
Example
67890
67890 % 4 = 2 = 10 (binary)
(67890-2)/4 = 16792 = 41114(octal)
so 67890 = 4111410 (martian)