Iran claims that 24 of them are active in their inventory and the actual numbers must be around 12-15. Even there were 24, they can do nothing. That's why Iran needs a newer fleet of a fighter which has easier maintenance.
This claim is not by Iran my brother, and Iran does not publish numbers like that, especially of one of its most strategic assets. The IRIAF in all probability has some 60 F-14s in its inventory and in times of war, I would guess they can all be made airworthy.
The 24 figure originates from the Flight Global website, as indicated in this July 2019 article below:
It was then attributed by mistake to Iran itself in another subsequent paper:
While tensions between the United States and Iran reach a boiling point, it can be hard to believe that just over forty years ago, America was so friendly
In 2013 The Aviationist released a plausible estimate of 60 units:
Thirty Minutes To Choose Your Fighter Jet: How The Shah Of Iran Chose The F-14 Tomcat Over The F-15 Eagle
Why the F-14 Tomcat won over the F-15 Eagle in Iran. Despite all the skepticism about the actual airworthiness of Iran's new stealth fighter "Qaher 313",