# Prime Not Prime vs Collatz Explorer

The clearest difference is rating: Collatz Explorer at 4.6 against Prime Not Prime's 4.3. On price, review sentiment, ratings volume and update cadence there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Collatz Explorer holds the better App Store score, 4.6 against 4.3. Both are backed by a comparable volume of ratings — 6 and 7 respectively. Written reviews split almost evenly too, at 100% and 100% positive.

Both ship on a similar rhythm, roughly monthly. The most recent releases landed on October 11, 2026 and September 27, 2026 respectively.

## The numbers

| Metric | Prime Not Prime | Collatz Explorer |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.3 (6 ratings)](https://appshunter.io/ios/app/prime-not-prime/id6738664674/reviews) | **[4.6 (7 ratings)](https://appshunter.io/ios/app/collatz-explorer/id6755121221/reviews)** |
| Number of ratings | 6 | **7** |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Monthly | Monthly |
| Monetization | Free | Free |
| Size | 15 MB | 1 MB |
| Requires iOS | **17.0** | 18.6 |
| Devices | iPhone | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Richard Witherspoon](https://appshunter.io/developer/1690898003) | [Berk Sucu](https://appshunter.io/developer/1852063488) |

## What reviewers say

### Prime Not Prime

[App page](https://appshunter.io/ios/app/prime-not-prime/id6738664674)

A fast-paced game that combines number recognition with a swiping mechanic. Players swipe right for prime numbers and left for non-primes, aiming to build long streaks. It's designed to be both educational and entertaining, with leaderboards for competitive play.

**Highlights:** Addictive swiping gameplay, Test prime number knowledge, Build streaks and complete challenges, Global leaderboards, Vibrant visuals and animations

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### Collatz Explorer

[App page](https://appshunter.io/ios/app/collatz-explorer/id6755121221)

Explore mathematical sequences with this app. It calculates the standard Collatz sequence for any number you enter and can also display sequences from an alternative 3x-1 function.

**Highlights:** Calculate Collatz sequences, Calculate 3x-1 function sequences, Input any number, Visualize sequences

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Prime Not Prime free?

Prime Not Prime is free to download, with no in-app purchases.

### Is Collatz Explorer free?

Collatz Explorer is free to download, with no in-app purchases.

### Which has better reviews, Prime Not Prime or Collatz Explorer?

Collatz Explorer is rated higher. Prime Not Prime averages 4.3 out of 5 from 6 ratings, while Collatz Explorer averages 4.6 from 7 ratings.

### Do Prime Not Prime or Collatz Explorer have ads?

Neither Prime Not Prime nor Collatz Explorer shows ads.

### Which is updated more often, Prime Not Prime or Collatz Explorer?

Prime Not Prime ships an update monthly, and Collatz Explorer monthly. Most recently, Prime Not Prime was updated on October 11, 2026 and Collatz Explorer on September 27, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*