Number of elements in the cyclotomic $F$ class.

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Let $F$ be a finite field with $p^n$ elements with prime $p > 5$ and $G = S_5$ the symmetric group. Let $l$ be the l.c.m. of the orders of the elements of G and $\theta$ be the primitive $l^{th}$ root of unity over $F$. Define the multiplicative group $$T = \{k\ | \theta \to \theta^k \ \text{ is automorphism of} \ F(\theta) \ \text{over} \ F\}$$ Then what is $|T|$?