  We prove exactly that the squared entanglement of formation, which quantifies
the bipartite entanglement, obeys a general monogamy inequality in an arbitrary
multiqubit mixed state. Based on this kind of exotic monogamy relation, we are
able to construct two sets of useful entanglement indicator: the first one can
detect all genuine multiqubit entangled states even in the case of the
two-qubit concurrence and $n$-tangles being zero, while the second one can be
calculated via quantum discord and applied to multipartite entanglement
dynamics. Moreover, we give a computable and nontrivial lower bound for
multiqubit entanglement of formation.
