# Primality vs AppAtlas Explorer

The clearest difference is in-app purchases: Primality at none against AppAtlas Explorer's 3. Primality also leads on ads (none vs shown) and iOS requirement (13.2 vs 18.6). AppAtlas Explorer's advantage is update cadence (every 4 days vs every 2 months). On price and device support there is nothing between them.

Both are free to download. AppAtlas Explorer sells 3 in-app purchases, starting at $0.99 per month. Primality asks for nothing beyond the download.

Primality ships an update every 2 months, AppAtlas Explorer every 4 days. The most recent releases landed on October 13, 2026 and October 1, 2026 respectively.

## The numbers

| Metric | Primality | AppAtlas Explorer |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.9 (24 ratings)](https://appshunter.io/ios/app/primality/id1516003672/reviews)** | — |
| Number of ratings | **24** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 2 months | **Every 4 days** |
| Monetization | Free | — |
| Size | 1 MB | 13 MB |
| Requires iOS | **13.2** | 18.6 |
| Devices | iPhone, iPod | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Bruce Schechter](https://appshunter.io/developer/1515359087) | [YUTAKA MIMURA](https://appshunter.io/developer/1865174244) |

## What reviewers say

### Primality

[App page](https://appshunter.io/ios/app/primality/id1516003672)

This app determines if a given integer is prime or provides its prime factors. It also calculates the ordinal position of prime numbers found, up to a certain limit.

**Highlights:** Primality testing, Prime factorization, Prime ordinality calculation, Large integer support (up to 999,999,999,999), Clean and simple interface

**Features:** macOS Compatibility

**In-app purchases:** none


### AppAtlas Explorer

[App page](https://appshunter.io/ios/app/appatlas-explorer/id6760437100)

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| AppAtlas ExplorerPro (Monthly) | $0.99 | per month |
| Support Development (Small) | $0.99 | one-time |
| Support Development (Large) | $9.99 | one-time |


## Frequently asked questions

### Is Primality free?

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

### Is AppAtlas Explorer free?

AppAtlas Explorer is free to download, with in-app purchases available.

### Do Primality or AppAtlas Explorer have ads?

AppAtlas Explorer shows ads; Primality does not.

### Which is updated more often, Primality or AppAtlas Explorer?

Primality ships an update every 2 months, and AppAtlas Explorer every 4 days. Most recently, Primality was updated on October 13, 2026 and AppAtlas Explorer on October 1, 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.*