The modified Bernoulli numbers \begin{equation*} B_{n}^{*} = \sum_{r=0}^{n}
\binom{n+r}{2r} \frac{B_{r}}{n+r}, \quad n > 0 \end{equation*} introduced by D.
Zagier in 1998 were recently extended to the polynomial case by replacing
Br by the Bernoulli polynomials Br(x). Arithmetic properties of the
coefficients of these polynomials are established. In particular, the 2-adic
valuation of the modified Bernoulli numbers is determined. A variety of
analytic, umbral, and asymptotic methods is used to analyze these polynomials