Standard Form by Boxed Rockets

Are These Numbers in Standard Form?

0.59 \times 10^{4}

No

66.6 \times 10^{-3}

No

0.853 \times 10^{3}

No

0.897 \times 10^{-6}

No

7.8 \times 10^{-3}

Yes

0.41 \times 10^{5}

No