According to NIST, the g-factor of the electron is:

electron g factor
Value	-2.0023193043737
Standard uncertainty	0.0000000000082
Relative standard uncertainty	4.1x10-12
Concise form	-2.0023193043737(82)

and NIST gives the magnetic moment of the electron as:

electron magnetic moment
Value	-928.476362x10-26 JT-1
Standard uncertainty	0.000037x10-26 JT-1
Rel standard uncertainty	4.0x10-8
Concise form	-928.476362(37)x10-26 JT-1

The quantum dimensions equation for electron magnetic moment in single charge dimensions is:

electron gyromagnetic ratio
Value	1.760859794x1011 s-1 T-1
Standard uncertainty	0.000000071x1011 s-1 T-1
Rel standard uncertainty	4.0x10-8
Concise form	1.760859794(71)x1011 s-1 T-1

According to NIST the electron gyromagnetic moment is given as a positive value by taking the absolute value of electron magnetic moment, which was made negative by the negative g-factor for the electron. The negative value for the gfactor is supposedly based on the negative charge of the electron. But then what logic would make the neutron g-factor negative? Can the electron and neutron g-factors be negative from different causes? That doesn't seem likely. As seen below, there is no mathematical reason for the electron gfactor to be negative, but there is a possible reason for the neutron gfactor to be negative.

While researching the physics of time, I found that Phi and phi are related to time. Phi is the Golden Ratio. It turns out that the electron g-factor is due to the stretching of spacetime as the electron spins at the speed of light. Mathematically, the electron g-factor is:

and the proton g-factor is:

Giving the symbol Φ for Phi and φ for phi, a possible solution for the neutron gfactor is:

In the previous equations, notice how the electron g-factor is dependent upon electron magnetic moment, and electron magnetic moment is dependent on the electron g-factor. Modern science has not yet found the true cause of the g-factor.

Also, as described on the magnetic moment page, NIST appears to have messed up on the value of the neutron magnetic moment and neutron g-factor as well.

Reference:

Eric W. Weisstein scienceworld.wolfram.com
The NIST Reference on Constants, Units, and Uncertainty