K for "thousand"
pts for "points".
The unit is thousands of points.
How would I convert that to a wavelength unit such as meters?
You can't. This is the maximum number of samples that can be used by the waveform generator function of the instrument.
It isn't directly related to the wavelength of the signals the generator can produce (assuming the sample rate is adjustable, which isn't clear).
It does give relationship between the lowest and highest frequency components in the signal generated. This limit would be about 8000:1. This would also limit the minimum duty cycle if you were using it to produce low duty cycle pulses.
It doesn't say anything at all about the actual oscilloscope waveform measuring function, or the data produced when measuring a signal with the oscilloscope.
Is a value of 3622260667 reasonable?
If that's the frequency of your signal in Hz, then no, it isn't reasonable to measure this with the scope you linked to. The scope has a bandwidth of about 300 MHz. It won't be useful to capture a signal with frequency 10x that.