http://stackoverflow.com/q/34236350/1271826

gistfile1.swift

@IBAction func calculateButton(sender: AnyObject) {
    if let value = Int(number.text!) {
        var isPrime = true
        
        if value == 1 {
            isPrime = false
        }
        
        for var i = 2; i < value; i++ {
            if value % i == 0 {
                isPrime = false
            }
        }
        
        if isPrime {
            resultLabel.text = "\(value) is prime!"
        } else{
            resultLabel.text = "\(value) is not prime!"
        }
    } else {
        resultLabel.text = "Please enter a number in the box"
    }
}

Thanks for helping me out!

@Rcub3161 No problem.