TRIGGER ----



trigger NumberToWordFieldUpdate on Invoice__c (before insert, before update) {
    for (Invoice__c sc : Trigger.new) {
        if (sc.Total_GST_value_Rs__c != null && sc.Total_GST_value_Rs__c >= 0) {
            integer i = integer.valueOf(sc.Total_GST_value_Rs__c);
            NumberToWord ntw = new NumberToWord();
            sc.Total_GST_value_words__c = ntw.convert(i);
        } else {
            sc.Total_GST_value_words__c = null;
        }
    }
}



CLASS 


public class NumberToWord {
    public string wordText{set;get;}
    public string convert() {
        wordText=convert(numberval);
        return null;
    }
    public long numberval { get; set; }
    public String[] units = new String[]{' Zero ',' One ',' Two ',' Three ',' Four ',' Five ',' Six ',' Seven ',' Eight ',' Nine ',' Ten ','Eleven ','Twelve ','Thirteen ','Fourteen ','Fifteen ','Sixteen ','Seventeen ','Eighteen ','Nineteen '};
    public String[] tens = new String[]{'','','Twenty','Thirty','Forty','Fifty','Sixty','Seventy','Eighty','Ninety'};
    public  String convert(long i) {
        if( i < 20)  return units[integer.valueOf(i)];
        if( i < 100) return tens[integer.valueOf(i)/10] + ((math.mod(i , 10) > 0)? '' + convert(math.mod(i , 10)):'');
        if( i < 1000) return units[integer.valueOf(i)/100] + ' Hundred and' + ((math.mod(i , 100) > 0)?' ' + convert(math.mod(i , 100)):'');
        if( i < 10000) return units[integer.valueOf(i)/1000] + ' Thousand ' + ((math.mod(i , 1000) > 0)?' ' + convert(math.mod(i , 1000)):'');
        if( i < 100000) return convert(i / 1000) + ' Thousand ' + ((math.mod(i , 1000) > 0)? '' + convert(math.mod(i ,1000)):'') ;
        if( i < 1000000) return units[integer.valueOf(i)/100000] + ' Lakh ' + ((math.mod(i , 100000) > 0)? '' + convert(math.mod(i ,100000)):'') ;
        if( i < 10000000) return convert(i / 100000) + ' Lakh ' + ((math.mod(i , 100000) > 0)? '' + convert(math.mod(i ,100000)):'') ;
        if( i < 100000000) return units[integer.valueOf(i)/10000000] + ' Crore ' + ((math.mod(i , 10000000) > 0)? '' + convert(math.mod(i , 10000000)):'') ;
        if( i < 1000000000) return convert(i / 10000000) + 'Crore ' + ((math.mod(i , 10000000) > 0)? '' + convert(math.mod(i , 10000000)):'') ;
        return 'Sorry, Too Big';
    }
}


input  104400


expected op    One Lakh Four Thousand and Four Hundred


output One Lakh Four Thousand Four Hundred and

TRIGGER ----



trigger NumberToWordFieldUpdate on Invoice__c (before insert, before update) {
    for (Invoice__c sc : Trigger.new) {
        if (sc.Total_GST_value_Rs__c != null && sc.Total_GST_value_Rs__c >= 0) {
            integer i = integer.valueOf(sc.Total_GST_value_Rs__c);
            NumberToWord ntw = new NumberToWord();
            sc.Total_GST_value_words__c = ntw.convert(i);
        } else {
            sc.Total_GST_value_words__c = null;
        }
    }
}



CLASS 


public class NumberToWord {
    public string wordText{set;get;}
    public string convert() {
        wordText=convert(numberval);
        return null;
    }
    public long numberval { get; set; }
    public String[] units = new String[]{' Zero ',' One ',' Two ',' Three ',' Four ',' Five ',' Six ',' Seven ',' Eight ',' Nine ',' Ten ','Eleven ','Twelve ','Thirteen ','Fourteen ','Fifteen ','Sixteen ','Seventeen ','Eighteen ','Nineteen '};
    public String[] tens = new String[]{'','','Twenty','Thirty','Forty','Fifty','Sixty','Seventy','Eighty','Ninety'};
    public  String convert(long i) {
        if( i < 20)  return units[integer.valueOf(i)];
        if( i < 100) return tens[integer.valueOf(i)/10] + ((math.mod(i , 10) > 0)? '' + convert(math.mod(i , 10)):'');
        if( i < 1000) return units[integer.valueOf(i)/100] + ' Hundred and' + ((math.mod(i , 100) > 0)?' ' + convert(math.mod(i , 100)):'');
        if( i < 10000) return units[integer.valueOf(i)/1000] + ' Thousand ' + ((math.mod(i , 1000) > 0)?' ' + convert(math.mod(i , 1000)):'');
        if( i < 100000) return convert(i / 1000) + ' Thousand ' + ((math.mod(i , 1000) > 0)? '' + convert(math.mod(i ,1000)):'') ;
        if( i < 1000000) return units[integer.valueOf(i)/100000] + ' Lakh ' + ((math.mod(i , 100000) > 0)? '' + convert(math.mod(i ,100000)):'') ;
        if( i < 10000000) return convert(i / 100000) + ' Lakh ' + ((math.mod(i , 100000) > 0)? '' + convert(math.mod(i ,100000)):'') ;
        if( i < 100000000) return units[integer.valueOf(i)/10000000] + ' Crore ' + ((math.mod(i , 10000000) > 0)? '' + convert(math.mod(i , 10000000)):'') ;
        if( i < 1000000000) return convert(i / 10000000) + 'Crore ' + ((math.mod(i , 10000000) > 0)? '' + convert(math.mod(i , 10000000)):'') ;
        return 'Sorry, Too Big';
    }
}


input  104400


expected op    One Lakh Four Thousand and Four Hundred


output One Lakh Four Thousand Four Hundred and