Total number of species from the following which can undergo disproportionation reaction: $$H_2O_2$$, $$ClO_3^-$$, $$P_4$$, $$Cl_2$$, $$Ag$$, $$Cu^{+1}$$, $$F_2$$, $$NO_2$$, $$K^+$$

Species that can undergo disproportionation have an element in an intermediate oxidation state:

$$H_2O_2$$: O is in -1 state (can go to 0 and -2) — YES

$$ClO_3^-$$: Cl is in +5 — YES (can disproportionate)

$$P_4$$: P is in 0 state — YES (goes to -3 and +5 in alkali)

$$Cl_2$$: Cl is in 0 state — YES (goes to -1 and +1)

$$Ag$$: metallic, 0 state — NO (already in lowest practical state)

$$Cu^{+1}$$: Can go to Cu(0) and Cu(+2) — YES

$$F_2$$: F is in 0 state, but F only goes to -1 (no positive states) — NO

$$NO_2$$: N is in +4 — YES (goes to +5 and +3)

$$K^+$$: Cannot disproportionate — NO

Total = 6 (H$$_2$$O$$_2$$, ClO$$_3^-$$, P$$_4$$, Cl$$_2$$, Cu$$^{+1}$$, NO$$_2$$).

Therefore, the answer is $$\boxed{6}$$.