Props.changeNumOfEvents not passed as a function. What do I write in app.js?

   return (
        <div className="number-of-events">
            <p className="input-label">Number of Events</p>
            <ErrorAlert text={this.props.infoText} />
            <input id="render-number" type="number" className="rendernumber" value={this.props.NumberOfEvents} onChange={(e) => this.props.changeNumOfEvents(e)}></input>
        </div>
    );
}
}

this.props.changeNumofEvents is not passed as a function. What should I write/add in app.js?