php-money-breakdown-mil-bil.php

<?php

function formatMoney( int $number = null ) {
	
	// display numbers as K or B or M
	if ($number < 1000) {
		// Anything less than a thousand
		$format_num = number_format($number);
	} else if ($number < 1000000) {
		// Anything less than a million
		$format_num = number_format($number / 1000, 0) . 'K';
	} else if ($number < 1000000000) {
		// Anything less than a billion
		$format_num = number_format($number / 1000000, 1) . 'M';
	} else {
		// At least a billion
		$format_num = number_format($number / 1000000000, 1) . 'B';
	}
	
	return $format_num;

}

$number = 15057450000;

if ($number) {
	echo formatMoney($number);
}