Each data type has it's own value range.
SMALLINT -32,768 - 32,767
INT -2,147,483,648 - 2,147,483,647
BIGINT -9,223,372,036,854,775,808 - 9,223,372,036,854,775,807
For a NUMERIC and DECIMAL field the maximum precision is 38. Depending on the value of the scale will deturmin the min and max value that you can store in the field.