# Prime Number Checker vs Cabri Express Primary

The clearest difference is device support: Cabri Express Primary at 4 against Prime Number Checker's 2. Prime Number Checker's advantage is iOS requirement (9.0 vs 14.0). On price, update cadence, ads and in-app purchases there is nothing between them.

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

Prime Number Checker ships an update every 5 weeks, Cabri Express Primary every 2 months. Both last shipped on October 3, 2026.

## The numbers

| Metric | Prime Number Checker | Cabri Express Primary |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 5 weeks** | Every 2 months |
| Size | 10 MB | 101 MB |
| Requires iOS | **9.0** | 14.0 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod, Mac** |
| Age rating | 4+ | 12+ |
| Developer | [Adam Thuvesen](https://appshunter.io/developer/1110341546) | [Cabrilog SAS](https://appshunter.io/developer/1058047739) |

## What reviewers say

### Prime Number Checker

[App page](https://appshunter.io/ios/app/prime-number-checker/id1114293126)

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

**In-app purchases:** none


### Cabri Express Primary

[App page](https://appshunter.io/ios/app/cabri-express-primary/id1668145657)

**Features:** Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Prime Number Checker free?

Prime Number Checker is free to download, with no in-app purchases.

### Is Cabri Express Primary free?

Cabri Express Primary is free to download, with no in-app purchases.

### Do Prime Number Checker or Cabri Express Primary have ads?

Neither Prime Number Checker nor Cabri Express Primary shows ads.

### Which is updated more often, Prime Number Checker or Cabri Express Primary?

Prime Number Checker ships an update every 5 weeks, and Cabri Express Primary every 2 months. Most recently, Prime Number Checker was updated on October 3, 2026 and Cabri Express Primary on October 3, 2026.

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