# Mersenne Primes vs Wordshelf

The clearest difference is in-app purchases: Wordshelf at none against Mersenne Primes's 1. Wordshelf also leads on ratings volume (125 vs 1) and update cadence (every 4 days vs weekly). Mersenne Primes's advantage is iOS requirement (9.0 vs 17.0). On price, rating, review sentiment and ads there is nothing between them.

Both are free to download. Mersenne Primes sells 1 one-off in-app purchase. Wordshelf asks for nothing beyond the download.

On the App Store both sit at effectively the same score — 5.0 for Mersenne Primes against 4.9 for Wordshelf. That said, the two scores are not equally well evidenced: Wordshelf has 125 ratings behind it against 1, so its average is the more settled of the two. Written reviews split almost evenly too, at 100% and 100% positive.

Mersenne Primes ships an update weekly, Wordshelf every 4 days. The most recent releases landed on October 16, 2026 and October 30, 2026 respectively.

## The numbers

| Metric | Mersenne Primes | Wordshelf |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/mersenne-primes/id1362004527/reviews)** | [4.9 (125 ratings)](https://appshunter.io/ios/app/wordshelf-ai-dictionary/id6444873974/reviews) |
| Number of ratings | 1 | **125** |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Weekly | **Every 4 days** |
| Monetization | Free with in-app purchases | **Free** |
| Size | 60 MB | 111 MB |
| Requires iOS | **9.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 17+ |
| Developer | [华 魏](https://appshunter.io/developer/454719266) | [Sourse Labs LLC](https://appshunter.io/developer/1535336712) |

## What reviewers say

### Mersenne Primes

[App page](https://appshunter.io/ios/app/mersenne-primes/id1362004527)

Explore and view the digits of all known Mersenne prime numbers. Witness the generation process for extremely large primes, page by page, and locate specific digits by their sequence number.

**Highlights:** View all digits of known Mersenne Primes, Witness prime number generation process, Page-by-page digit exploration, Locate specific digits by sequence number, Generates primes using mobile CPU

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| One Support | $0.99 | one-time |


### Wordshelf

[App page](https://appshunter.io/ios/app/wordshelf-ai-dictionary/id6444873974)

Effortlessly capture, understand, and remember new words encountered while reading or studying. Utilize AI-powered mnemonics and visual aids to enhance retention. Track your vocabulary growth and organize learned words by the book you're reading.

**Highlights:** Scan pages or type words to look up, Definitions, pronunciation, examples, synonyms, etymology, Personalized AI mnemonics and memory images, Words organized by book, Vocabulary progress tracking, Supports 20+ languages

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

**In-app purchases:** none


## Frequently asked questions

### Is Mersenne Primes free?

Mersenne Primes is free to download, with in-app purchases available.

### Is Wordshelf free?

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

### Which has better reviews, Mersenne Primes or Wordshelf?

Mersenne Primes is rated higher. Mersenne Primes averages 5.0 out of 5 from 1 ratings, while Wordshelf averages 4.9 from 125 ratings.

### Do Mersenne Primes or Wordshelf have ads?

Neither Mersenne Primes nor Wordshelf shows ads.

### Which is updated more often, Mersenne Primes or Wordshelf?

Mersenne Primes ships an update weekly, and Wordshelf every 4 days. Most recently, Mersenne Primes was updated on October 16, 2026 and Wordshelf on October 30, 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.*