Constant FRAC_2_SQRT_PI 

pub const FRAC_2_SQRT_PI: f128 = 1.12837916709551257389615890312154517168810125865799771368817_f128 /* 1.12837916709551257389615890312154526f128 */;

🔬This is a nightly-only experimental API. (f128 #116909)

2/sqrt(π)