Intelligence: Above Average (Four can understand Insulavoric (Dora's language), Roboty's Morse code, Teardrop's sign language, and Woody's speech perfectly, even though Insulavoric is supposed to be one of the hardest languages to learn.)

Powers and Abilities

Screechy: Stuns any contestant who's targeted by said screech. It can also generate hearts when Four shows love or excitement towards something, which can fling a contestant as shown with Eraser.

Zappies: Beams that shoot out of their hands and electrocute anybody who is hit by them, making them lose health. Although Four has to seemingly charge up at times (possibly for a longer duration, constant beam), they can also fire them instantly.

Advanced-level reality-warping: Four can create objects such as cakes, buttons, pillars, Paper Planes, Buzzer Boxes, soup, orange dye, and jawbreakers out of thin air. Not only can they revive contestants, but they can also revive them in a place other than their hand, as seen in "Lick Your Way to Freedom" when they revived the contestants in giant jawbreakers, which they also created. Also, as seen with the paper planes in "Fortunate Ben", they can likely manipulate the laws of physics.

Gravity manipulation: Donut, while inhabited by the factor of Four, was able to turn on and off the effects of gravity. This ability can be refined to only affect certain entities, as Donut only manipulated gravity's effects on the Moon.

(Four was able to crush down a planet-sized Black Hole into a significantly less voluminous state and near nullifying Black Hole's normally intense gravity, allowing Black Hole to compete.)

Shape-shifting: As shown in "What Do You Think of Roleplay?", both Four and X can shape-shift, or change their physical appearance. Also, they can change the shape of other characters as well.

Size manipulation: In "Return of the Rocket Ship", Four grows to an absurd size in response to Pillow's criticism. In "Take the Tower", Four grows to a large size when stopping Blocky and creating the towers. In "The Tweested Temple", Four grows to an extremely large size after Four receives Gelatin's cursed totem and declares he is up for elimination.

Brain manipulation: In "What Do You Think of Roleplay?", Four displayed the power to augment and transfer the brains/personalities of the contestants into each other; however, instead of going back to their original bodies, the body that the person's mind was in shape-shifted into that mind's original body.

Perspective violation: Four can violate common 2D perspective laws such as sliding in front of objects on the ground and suddenly switching to behind objects on the ground.

Incredible volume: Four can raise their voice so that it can even be heard through the far reaches of space.

Controlling and morphing clouds: They have used this to time contests that require a time limit to show how much time is currently left.

Donut is seen doing this in "Four Goes Too Far", but it's most likely via the "factor of Four".

Earthbending: In "Take the Tower", Four rose their hands up to cause two hills to rise under the team's towers.

Physical video conversion: In "Chapter Complete", the BFDI was revealed to be BFDI and BFDIA converted into a deep-fried box by Four.

Warping: Profily is killed in "Chapter Complete" touching a Four cactus. They ascended, warped, and popped.

Malleability: As seen in "Enter the Exit", "The Four is Lava", and "Take the Tower", Four's body and limbs can stretch to extreme distances and can change shape at will. They can also contract extremely thin in "The Escape from Four".

Recovery: Four replaces the Recovery Centers from previous seasons by using only their hand to recover contestants and numbers, and also teaches X how to master said ability in "B.F.B. = Back From Beginning".

Mutilation: Turns any contestant into an abstract version of themselves, killing them. A harp strum plays in the process.

Elimination: Four replaces the Tiny Loser Chamber and Locker of Losers from previous seasons, by sucking up eliminated contestants or "eating" them. From there, the eliminated contestants are sent to Eternal Algebra Class Withfour (EXIT). EXIT also appears to be an alternate plane of existence, because the contestants probably shrink.

Inception/Astral projection: Four cannot only enter themself to talk to the "EXITors", but is also able to still do that when they are already inside themself, as shown when they inserted their arm inside themself again to pick up Leafy in "Get to the Top in 500 Steps". Their arm also appeared to be larger than normal, which suggests that anything that enters shrinks (except Four).

Super-speed: Four can fly at extreme speeds, as shown in "Enter the Exit". Also, in "Chapter Complete", when they merge with the Big Rotating Building, they can travel from the Earth to the Sun in approximately 12 seconds, flying at a speed of approximately 45,000,000,000 km/h, or 27,900,000,000 mph.

This means that Four can travel almost 42 times the speed of light.

Teleportation: He can teleport whenever a "4" has been played shown in "Today's Very Special Episode". They could also teleport others with a snap of their fingers in "What Do You Think of Roleplay?", "A Taste of Space", "Uprooting Everything", and "Chapter Complete".

Incredible strength: In "Questions Answered", Donut is seen pushing the entire Earth (the Earth's weight is 5.972e+24 kg, or 1.3166e+25 lb) into his camera using only his feet via the factor of Four. This trait also applies to Four's ability to warp reality. Four was also able to stop the FreeSmart Supervan just by putting their hand out, crushing it in the process.

Dismemberment: This happened off-screen when X interrupted Four, who snapped off X's leg. This is unknown to be a power or not, however, as it wasn't known exactly how Four snapped X's leg.

Flight: In "Enter the Exit", Four was able to fly over to the Waterfall to eliminate Roboty.

Regeneration: In "Enter the Exit", when the contestants were recovering Four, they were in a liquidated state up until the point when they were reformed back to normal.

Fire resistance (external): Four is able to stand on the lava and dig their hands into it as well. They were also able to survive standing on the sun and even merging with it without any issue, as shown in "Chapter Complete".

Thought manipulation: During the Cake at Stake in "The Four is Lava", Four displayed the ability to create positive thoughts (or happy thoughts) and send them to the safe contestants of . It is unknown if Four has the ability to create other kinds of thoughts at the moment.

Airbending: As shown in "A Taste of Space", Four can give people air, even in the vacuums of space.

Brain scanning: As shown in "Who Stole Donut's Diary?", Four shoots a laser (similar style to Zappies) at X's head and receives their thoughts to find out who stole Donut's diary.

Incredible hearing: As shown in "A Taste of Space" and "Fashion For Your Face!", Four's ears are able to hear from miles away, up to the sun.

Telekinesis: Just like X, Four can make things float by snapping his fingers, as shown in "The Game Has Changed".

Despawning: As shown in "The Game Has Changed", Four can "despawn" a contestant by bringing them off-screen which results in them dying. While the method of how they do it is unknown, we see a white glow where they are despawning them. This ability was further explored later on. As shown in "The Tweested Temple", laser gun sounds play when Four despawned X. This ability was revealed and confirmed later on. As shown in "B.F.B. = Back From Beginning", when X despawned Teardrop, it has been revealed that both Four and X have white laser eyes that make a character look black and completely disappear when it hits them.

Possession: In "Chapter Complete", Four possessed a tree, the courthouse, the High Speed Express Train, the BRB and the sun. When doing so, the things he possesses become blue.

Assimilation: As shown in "B.F.B. = Back From Beginning", Four was able to merge with the Desert and reshape it closer to their own appearance.

Standard Equipment

None

Notable Techniques

Screechy, Advanced-level reality-warping, Brain scanning, Regeneration, Flight, Despawning, Thought manipulation, Possession, and Shape-shifting

Other

Standard Tactics: Screeches and occasionally zappies

Weaknesses:

Factorization: Four will become assimilated if they get multiplied with 0, or anything that simply resembles a 0. If they come into contact with the insides of Donut (zero), they will turn into a liquid until taken out and squirted back into their normal shape.
Limited stamina/Exhaustion: Four was unable to eliminate and suck in Spongy completely in "The Escape from Four", possibly due to Spongy's massive size.
Burn tolerance: Four can become incapacitated if they come into contact with fire (presumably from the inside, which is unusual given their resistance to lava), and receives a psychedelic effect. The only known cure is a juice box.