transfer function of a op amp
Without any reactive components (ie. capacitors or inductors) in your feedback circuitry, the cutoff frequency will be set almost entirely by the characteristics of the op-amp itself. As Caleb commented, the gain bandwidth product from the datasheet will give you an estimate.

If you have a specific op-amp in mind I'd directly measure your cutoff frequency. Change the frequency of the input signal until you find the frequency where the gain drops -3dB and you've found your cutoff frequency.