It is well defined. In a hydrogen atom the coloumb (charge) force is about 10^39.5 times stronger than the gravitational force. Of course we cannot measure the gravitational force in a hydrogen atom, it is based on the mass of each particle and the known value of G. The fact that G is only known with limited precision does not make the answer wrong. It does not depend on any of the modern weird physics either.
For those that do not know, there is a thing called LNH (Large Numbers Hypothesis) that notices that numbers near 10^40 and 10^80 pop up several times. This was popular with Dirac and Eddington: [link to en.wikipedia.org
I don't like the way it is often framed as time. It should be size of observable Universe, or Hubble scale.
1. Ratio of coloumb force to gravity ~10^40
2. Size of Hubble scale compared to atomic scale, similar
3. No. of particles in observable Universe ~10^80
When it is understood that matter is made of spherical standing waves then the relationship between these is made clear. For example, at a distance scale of 10^40 of an atomic particle, the outgoing part of the standing wave has a surface area of 10^80 times the area of the particle. Therefore it will have hit the inner wave (become the inner wave) of other particles by that distance. So "vision" of particles is limited to that distance, the Hubble scale.
It is also possible to show why the redshift and gravity also fit that this number which is the rate at which energy is absorbed by matter.