Problem $19-9$ Calculating the Estate Tax $[$LO$19-5]$ Joel and Rachel are both retired. Married for $35$ years, they've amassed an estate worth $\backslash (\backslash$$ $10\mathrm{.}6\backslash )$ million. The couple has no trusts or other types of tax$-$sheltered assets. If Joel or Rachel dies in $2021,$ how much federal estate tax would the surviving spouse have to pay, assuming that the estate is taxed at the $40$ percent rate? Note: Leave no cells blank $-$ be certain to enter $"0"$ wherever required. Federal estate tax