Как преобразовать число в слово

Для преобразования 1 = сначала, 2 = второй... попробуйте эту функцию

 function stringifyNumber($n) {
    $special = ['zeroth','first', 'second', 'third', 'fourth', 'fifth', 'sixth', 'seventh', 'eighth', 'ninth', 'tenth', 'eleventh', 'twelfth', 'thirteenth', 'fourteenth', 'fifteenth', 'sixteenth', 'seventeenth', 'eighteenth', 'nineteenth'];
    $deca = ['twent', 'thirt', 'fort', 'fift', 'sixt', 'sevent', 'eight', 'ninet'];
    if ($n < 20) return $special[$n];
        if ($n%10 === 0) return $deca[round($n/10,0)-2] . 'ieth';
        return $deca[round($n/10,0)-2] . 'y-' . $special[$n%10];
}



echo $number=stringifyNumber($number);

Если вы хотите преобразовать число в такие слова:

564: пятьсот шестьдесят четыре

затем используйте эту функцию для преобразования числа в слова

function convert_number_to_words ($ number) {

$hyphen      = '-';
$conjunction = ' and ';
$separator   = ', ';
$negative    = 'negative ';
$decimal     = ' point ';
$dictionary  = array(
    0                   => 'zero',
    1                   => 'one',
    2                   => 'two',
    3                   => 'three',
    4                   => 'four',
    5                   => 'five',
    6                   => 'six',
    7                   => 'seven',
    8                   => 'eight',
    9                   => 'nine',
    10                  => 'ten',
    11                  => 'eleven',
    12                  => 'twelve',
    13                  => 'thirteen',
    14                  => 'fourteen',
    15                  => 'fifteen',
    16                  => 'sixteen',
    17                  => 'seventeen',
    18                  => 'eighteen',
    19                  => 'nineteen',
    20                  => 'twenty',
    30                  => 'thirty',
    40                  => 'fourty',
    50                  => 'fifty',
    60                  => 'sixty',
    70                  => 'seventy',
    80                  => 'eighty',
    90                  => 'ninety',
    100                 => 'hundred',
    1000                => 'thousand',
    1000000             => 'million',
    1000000000          => 'billion',
    1000000000000       => 'trillion',
    1000000000000000    => 'quadrillion',
    1000000000000000000 => 'quintillion'
);

if (!is_numeric($number)) {
    return false;
}

if (($number >= 0 && (int) $number < 0) || (int) $number < 0 - PHP_INT_MAX) {
    // overflow
    trigger_error(
        'convert_number_to_words only accepts numbers between -' . PHP_INT_MAX . ' and ' . PHP_INT_MAX,
        E_USER_WARNING
    );
    return false;
}

if ($number < 0) {
    return $negative . convert_number_to_words(abs($number));
}

$string = $fraction = null;

if (strpos($number, '.') !== false) {
    list($number, $fraction) = explode('.', $number);
}

switch (true) {
    case $number < 21:
        $string = $dictionary[$number];
        break;
    case $number < 100:
        $tens   = ((int) ($number / 10)) * 10;
        $units  = $number % 10;
        $string = $dictionary[$tens];
        if ($units) {
            $string .= $hyphen . $dictionary[$units];
        }
        break;
    case $number < 1000:
        $hundreds  = $number / 100;
        $remainder = $number % 100;
        $string = $dictionary[$hundreds] . ' ' . $dictionary[100];
        if ($remainder) {
            $string .= $conjunction . convert_number_to_words($remainder);
        }
        break;
    default:
        $baseUnit = pow(1000, floor(log($number, 1000)));
        $numBaseUnits = (int) ($number / $baseUnit);
        $remainder = $number % $baseUnit;
        $string = convert_number_to_words($numBaseUnits) . ' ' . $dictionary[$baseUnit];
        if ($remainder) {
            $string .= $remainder < 100 ? $conjunction : $separator;
            $string .= convert_number_to_words($remainder);
        }
        break;
}

if (null !== $fraction && is_numeric($fraction)) {
    $string .= $decimal;
    $words = array();
    foreach (str_split((string) $fraction) as $number) {
        $words[] = $dictionary[$number];
    }
    $string .= implode(' ', $words);
}

return $string;

}

Вывод::

echo convert_number_to_words (123456789);

//Сто двадцать три миллиона четыреста пятьдесят шесть тысяч семьсот восемьдесят девять