Q:

PHP: Express Number in Words

Is there a function that will express any given number in words?
For example:
If a number is 1432, then this function will return "One thousand four hundred and thirty two".

A:

Use the NumberFormatter class that are in php ;)
$f = new NumberFormatter("en", NumberFormatter::SPELLOUT);
echo $f->format(1432);

That would output "one thousand four hundred thirty-two"

A:

You can do this in many ways I am mentioning here two ways by using The NumberFormatter class as mentioned in Martindilling answer (if you have php version 5.3.0 or higher and also PECL extension 1.0.0 or higher) or by using the following custom function.
function convertNumberToWord($num = false)
{
    $num = str_replace(array(',', ' '), '' , trim($num));
    if(! $num) {
        return false;
    }
    $num = (int) $num;
    $words = array();
    $list1 = array('', 'one', 'two', 'three', 'four', 'five', 'six', 'seven', 'eight', 'nine', 'ten', 'eleven',
        'twelve', 'thirteen', 'fourteen', 'fifteen', 'sixteen', 'seventeen', 'eighteen', 'nineteen'
    );
    $list2 = array('', 'ten', 'twenty', 'thirty', 'forty', 'fifty', 'sixty', 'seventy', 'eighty', 'ninety', 'hundred');
    $list3 = array('', 'thousand', 'million', 'billion', 'trillion', 'quadrillion', 'quintillion', 'sextillion', 'septillion',
        'octillion', 'nonillion', 'decillion', 'undecillion', 'duodecillion', 'tredecillion', 'quattuordecillion',
        'quindecillion', 'sexdecillion', 'septendecillion', 'octodecillion', 'novemdecillion', 'vigintillion'
    );
    $num_length = strlen($num);
    $levels = (int) (($num_length + 2) / 3);
    $max_length = $levels * 3;
    $num = substr('00' . $num, -$max_length);
    $num_levels = str_split($num, 3);
    for ($i = 0; $i < count($num_levels); $i++) {
        $levels--;
        $hundreds = (int) ($num_levels[$i] / 100);
        $hundreds = ($hundreds ? ' ' . $list1[$hundreds] . ' hundred' . ' ' : '');
        $tens = (int) ($num_levels[$i] % 100);
        $singles = '';
        if ( $tens < 20 ) {
            $tens = ($tens ? ' ' . $list1[$tens] . ' ' : '' );
        } else {
            $tens = (int)($tens / 10);
            $tens = ' ' . $list2[$tens] . ' ';
            $singles = (int) ($num_levels[$i] % 10);
            $singles = ' ' . $list1[$singles] . ' ';
        }
        $words[] = $hundreds . $tens . $singles . ( ( $levels && ( int ) ( $num_levels[$i] ) ) ? ' ' . $list3[$levels] . ' ' : '' );
    } //end for loop
    $commas = count($words);
    if ($commas > 1) {
        $commas = $commas - 1;
    }
    return implode(' ', $words);
}

A:

In case of using Yii2 you can do this as simple as the following:
$sum = 100500;
echo Yii::$app->formatter->asSpellout($sum);

This prints spelled out $sum in your app's language.
Docs reference

