Why is year from my timestamp centuries off? PHP/WordPress

I’ve googled this a bunch and got nothing so I’m hoping y’all can help.

I’m calling this API (https://api.metals.live/v1/spot). I’m converting the timestamp using PHP’s date() function but I get back a date that is over 50,000 years in the future. I copied and pasted the same timestamp into this epoch converter (https://www.epochconverter.com) and it worked just fine. I’ve also tried using WP’s built-in wp_date() function, still 50k years in the future.

Anyone had this issue?

        $url = "https://api.metals.live/v1/spot";
        $response = file_get_contents('https://api.metals.live/v1/spot');
        //convert to PHP array
        $arr = json_decode($response,true);

        // Loop thru data and add it to new array
        $new_arr = [];
        foreach($arr as $x => $x_value) {
            foreach($x_value as $y => $y_value) {
                echo "Key=" . $y . ", Value=" . $y_value;
                echo "<br>";
                array_push($new_arr, (object)[
                    'metal' => $y,
                    'price' => $y_value
                ]);
            }
        }
        // print and format data in the array (for testing)
        foreach($new_arr as $x) {
            echo "<p>$x->metal : $x->price</p>" . "<br />";
        }

        // access gold price and convert to float
        $gold_price = floatval($new_arr[0]->price);
        // access silver price and convert to float
        $silver_price = floatval($new_arr[1]->price);
        //this is the timestamp value (despite it's name)
        $timestamp = $new_arr[4]->price;
        $date = date("Y-m-d H:i:s",$timestamp);
        echo $date;
    

>Solution :

The timestamp 1638476352474 is too long because it contains milliseconds. Divide it by 1000, and you’ll get a proper date.

 $date = date("Y-m-d H:i:s",$timestamp/1000);