How to fix formatting issue

While paste data i am getting wrong value format in column 1 & 7.

original value is 20190517046351641004
Value pasted as 20190517046351600000

(edit: activated screenshot)

Numbers in Calc are internally represented in IEEE-754 floating point format. This format offers 52 explicit bits + 1 implicit bit for the “mantissa”, i.e. the “significant” digits. 53 bits allow for ~17-18 decimal digits and you entered a 20-digit integer. Consequently, the 17-18 most significant digits are used to compute the closest possible mantissa and a scale factor (the “exponent”) is then associated to “shift” this integer to correct order of magnitude.

If you really need this degree of precision with your number, consider using multi-precision applications or mathematical symbolic manipulation programs.

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… and if you need the digit sequence as a kind of identificator (i.e., it’s not a number taking part in calculations, but just a sequence of symbols to uniquely designate something), then just format the column as text prior to entering the digits.

Looking at your example data as your question is refreshed by @AlexKemp’s editing, I seem to read there something like a date-time stamp. Date-time stamps are internally represented as a number of time units (I don’t remember which) from an epoch (time origin). The integer part is the number of days elapsed since the epoch and the fractional part is the fraction of the day.

Formatting routines take this number to convert it to human-readable meaningful printed sequence. This sequence may contain more than 17-18 decimal digits but the quantity of information is not bigger, e.g. for a human 2019 and 19 have the same significance). Also human “fragments” such as day, month and year are extracted from the number artificially expanding the number of character needed to “print” the data. Typing back this string will not fit in an IEEE-754 number.

If you have a date, type it as a date and Calc will do the necessary conversion without error.