SQL Server 2019

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CREATE TABLE XYZ
	([ExpirationDate] float);
	
INSERT INTO XYZ
	([ExpirationDate])
VALUES
	(1301598290687),
	(2240542800000),
	(2144034000000)
;
3 rows affected

select 
  DATEADD(MILLISECOND, 
          cast(ExpirationDate as bigint) % 1000, 
          DATEADD(SECOND, cast(ExpirationDate as bigint) / 1000, '19700101'))
from XYZ
Msg 8115 Level 16 State 2 Line 1
Arithmetic overflow error converting expression to data type int.

declare @yr_mnth_dt as varchar(20);
set @yr_mnth_dt = '2240542800000';
select convert(datetime,@yr_mnth_dt,112) as YR_MNTH_DT;

Msg 241 Level 16 State 1 Line 3
Conversion failed when converting date and/or time from character string.

SELECT CAST('2240542800000' AS DATETIME)
Msg 241 Level 16 State 1 Line 1
Conversion failed when converting date and/or time from character string.