12.5 terahertz. If your wavelength is in meters.

Terahertz and infrared radiation.

there are actually seven types of EMR

radio waves, microwaves, terahertz radiation, infrared radiation, visible light, ultraviolet radiation, x-rays & gamma rays

"terra ..." = trillion = 1012

That's a thousand billion.

Also a million million.

Also a thousand thousand thousand thousand.

1 terahertz = 1,000 GHz = 1 million MHz = 1 billion KHz

Electromagnetic radiation between 490-790 terahertz, or about 390-700 nanometers wavelength.