What are the speed, frequency, and wavelength of a photon of energy 140 keV?

As a massless particle photon energy is E = hf = hc/L= 140 KeV = 2.24307E-14 Joules.  

(Recommend you not return to that "someone" for physics advice again.  That someone has mixed eV with meters/sec, so the units are inconsistent.  You must convert to Joules to get L in meters and frequency in cycles per second (aka Hertz).)  [See the source below for an excellent unit conversion web site.]

So L = hc/E = ? meters; where h is Planck's constant in the kms SI units, c ~ 299E6 mps, and E is in Joules above.  You can do the math.

And f = E/h = ? cycles per sec (Hertz).  You can do the math.

The speed of the photon is, of course, c, the speed of light.