PHP回声数字与字母

Question

On my game, I have it to where when someone logs in, it displays their cash. It's Fetched from the database.

<div id="StatText">Cash: <span id="Cash">$<?php echo number_format($cash) ?></span></div>

Well, I updated the database for my account and gave myself $10,000,000,000,000 = 10 Trillion dollars. Well How would I make it to where a user's cash would show like this. If they had $16,500 It would display $16.5K And same with millions billions ETC.
Example: $16,500 = 16.5K
$160,500 = 160.5K
$1,600,500 = 1.6M
$10,000,016,500 = 10B
$9,110,000,016,500 = 9.1T
Nothing really showed up on Google. Thanks For Any Help!

Answer 1

(Late answer) This works (you're welcome to use it) Keep the accepted answer.

<?php
$n = 15500000000; // echoes $15.5B
// $n = 9110000016500; // echoes $9.1T

if ($n < 1000000) {
    // Anything less than a million
    $n_format = number_format($n);
} 

else if ($n < 1000000000) {
    // Anything less than a billion
    $n_format = number_format($n / 1000000, 1) . 'M';
} 

else if ($n < 1000000000000) {
    // Anything less than a trillion
    $n_format = number_format($n / 1000000000, 1) . 'B';
} 

else {
    // At least a trillion
    $n_format = number_format($n / 1000000000000, 1) . 'T';

} 

echo "$" .$n_format;

<kbd>Demo</kbd>

Call it my contribution