Why is michael considered the strongest angel?

There are angels much higher in rank, like the seraphim, who sit directly next to the throne of God, yet Michael is believed to be the strongest? What about Metatron? The mediator between mankind and the divine, who holds the universe in order. Seraphiel? The leader of the seraphim. Lucifer (before fall)? The angel of light, morningstar, who beared power almost equal to god's. These angels are of much higher importance and power.