Number to string

I am getting value from integration as '1234'

I am inserting it in to table where field is character(12). the assignment is as below

rec1.field.value = string(1234);

still I can see after entire process run , The value in the record is '1234.00'

I can not change datatype of record , how can I get value in record as '1234' instead of '1234.00' . I can not use round as it might change value