Edit in JSFiddle

let integers = [2, 4, 1, 6, 5, 40, -1];

let findIntegersThatMultiplyTo = (array, target) => {
	let resultingIntegers = [];
  
	array.some(integer => {
		let secondNumber = target / integer;
    
    if(array.indexOf(secondNumber) > -1)
    	resultingIntegers.push(integer, secondNumber);
    
    return resultingIntegers.length === 2;
  });
  
  return resultingIntegers;
};

document.write(findIntegersThatMultiplyTo(integers, 20));