Display the total price on the WooCommerce single product page with the original product price * minimum quantity

$product->get_price() will return price for 1 product.

You can use get_min_purchase_quantity() and multiply into price for first time.

add_action( 'woocommerce_single_product_summary', 'woocommerce_total_product_price', 31 );
function woocommerce_total_product_price() {
    global $woocommerce, $product; 
    // let's setup our divs 
$price = $product->get_price();
$min_qnty = $product->get_min_purchase_quantity();
$initial_price = floatval($price) * intval ($min_qnty);
    echo sprintf('<div id="product_total_price" style="margin-bottom:20px;">%s %s</div>',__('Prezzo Totale:','woocommerce'),'<span class="price">'.$initial_price.'</span>');
    ?>
    <script>
        jQuery(function($){
            var price = <?php echo $product->get_price(); ?>,
                currency = '<?php echo get_woocommerce_currency_symbol(); ?>';

            $('[name=quantity]').change(function(){
                if (!(this.value < 1)) {

                    var product_total = parseFloat(price * this.value);

                    $('#product_total_price .price').html( currency + product_total.toFixed(2));

                }
            });
        });
    </script>
    <?php
}

The following code takes into account the product quantity when loading the page, then the price is updated when changing the product quantity.

Explanation via comment tags added in the code

function action_woocommerce_single_product_summary() {
    global $product;
    
    // Getters
    $price = $product->get_price();
    $currency_symbol = get_woocommerce_currency_symbol();
    
    // let's setup our div
    echo sprintf('<div id="product_total_price" style="margin-bottom:20px;">%s %s</div>', __('Product Total:','woocommerce'), '<span class="price">' . $currency_symbol . $price . '</span>' );
    ?>
    <script>
    jQuery(function($) {
        // jQuery variables
        var price = <?php echo $price; ?>, 
            currency = '<?php echo $currency_symbol; ?>',
            quantity =  $( '[name=quantity]' ).val();
            
        // Code to run when the document is ready
        var product_total = parseFloat( price * quantity );
        $( '#product_total_price .price' ).html( currency + product_total.toFixed( 2 ) );
            
        // On change
        $( '[name=quantity]' ).change( function() {
            if ( ! ( this.value < 1 ) ) {
                product_total = parseFloat( price * this.value );

                $( '#product_total_price .price' ).html( currency + product_total.toFixed( 2 ) );
            }
        });
    });
    </script>
    <?php

}
// We are going to hook this on priority 31, so that it would display below add to cart button.
add_action( 'woocommerce_single_product_summary', 'action_woocommerce_single_product_summary', 31, 0 );