calc: |MAX| converted to 0,0000..0000E+00 in save-load cycle

edit

the max limit for a double float value is 1.79769313486231570 • 10^308

Yes, that is a significand of 1111111111111111111111111111111111111111111111111111 and exponent of 11111111110

but if i key that in a calc cell it's rounded by calc to 1.79769313486232E+308, without any message that this value is too large

The value is not too large, otherwise it wouldn't be accepted as numeric input. The display string of the underlying floating point value though is limited to a precision of 15 digits, that's why it appears rounded.

larger numbers are usually simply converted to text?

No. It's the other way around. Text input larger than an acceptable numeric value is not converted to numeric but stays text. Like with any text input, if it's not convertible to numeric or currency or date or time or ... it stays text.

@erAck:
still confused,
cell format 'number standard', keyed in 1,79769313486232E+308, shown as text, cell format changed itself to text,
cell format 'number standard', keyed in 1,7976931348623157E+308, widened decimal range, shown as number (right aligned), cell format changed itself to scientific, shown as '1,79769313486232E+308',
edited! that to '1,79769313486232E+308', still a number, cell format still scientific,
cell format 'scientific', keyed in 1,79769313486233E+308 or any bigger value, shown as number (right aligned), cell format still scientific, cutted down to '1,79769313486232E+308',
different handling of 'too big to nail' values acc. to cell format?
irritating for simple minds (like me) ...

It looks like editing a cell trying to overwrite it with a too large value is refused. I can't say for sure without inspecting things which I won't do right now. But if so it seems like a good feature to me.