Unfortunately, I wasn't able to reproduce your problem. I tried the same number with the same command line, but it worked for me.
I could think of two more problem sources:
1. Maybe there is something wrong with input/output. Just enter the number at command line ("echo <number> | ecm <...>") and don't redirect the output to a file.
2. Maybe your ecm file is somehow corrupt. Try recompiling it or take a suitable binary from
this thread.
Hope this helps!