In division with a divisor, the quotient is 21, the remainder is 15, and the sum of the dividend, divisor, quotient, and remainder is 557, so what is the dividend?
有除数除法中，商是21，余数是15，被除数、除数、商、余数的和是557，那么被除数是多少？
<gadget id="calculator">557 - 15 - 21 - 15</gadget>
<output>506</output>

<gadget id="calculator">21 + 1</gadget>
<output>22</output>

<gadget id="calculator">506 / 22</gadget>
<output>23</output>

<gadget id="calculator">21 * 23</gadget>
<output>483</output>

<gadget id="calculator">483 + 15</gadget>
<output>498</output>

<result>498</result>