# 瞬間素因数分解 Prime Factorization vs 青空えいご

The clearest difference is update cadence: 青空えいご at daily against 瞬間素因数分解 Prime Factorization's weekly. 青空えいご also leads on iOS requirement (15.1 vs 17.0). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. 瞬間素因数分解 Prime Factorization sells 1 one-off in-app purchase and 青空えいご sells 3 in-app purchases, starting at $0.49 per month. Whichever you choose, the download price is not the number that matters.

瞬間素因数分解 Prime Factorization ships an update weekly, 青空えいご daily. The most recent releases landed on October 25, 2026 and October 31, 2026 respectively.

## The numbers

| Metric | 瞬間素因数分解 Prime Factorization | 青空えいご |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | Yes |
| Ads | Yes | Yes |
| Update frequency | Weekly | **Daily** |
| Size | 3 MB | 37 MB |
| Requires iOS | 17.0 | **15.1** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 12+ |
| Developer | [YUSUKE MIZUNO](https://appshunter.io/developer/1729948508) | [Kenshiro Tammachi](https://appshunter.io/developer/6809838692) |

## What reviewers say

### 瞬間素因数分解 Prime Factorization

[App page](https://appshunter.io/ios/app/prime-factorization/id6478605149)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Remove Ad | $1.99 | one-time |


### 青空えいご

[App page](https://appshunter.io/ios/app/id6816096198)

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| プレミアム月額(広告なし) | $0.49 | per month |
| プレミアム年額(広告なし) | $2.99 | per year |
| プレミアム(広告なし・買い切り) | $5.99 | one-time |


## Frequently asked questions

### Is 瞬間素因数分解 Prime Factorization free?

瞬間素因数分解 Prime Factorization is free to download, with in-app purchases available.

### Is 青空えいご free?

青空えいご is free to download, with in-app purchases available.

### Do 瞬間素因数分解 Prime Factorization or 青空えいご have ads?

Both 瞬間素因数分解 Prime Factorization and 青空えいご show ads.

### Which is updated more often, 瞬間素因数分解 Prime Factorization or 青空えいご?

瞬間素因数分解 Prime Factorization ships an update weekly, and 青空えいご daily. Most recently, 瞬間素因数分解 Prime Factorization was updated on October 25, 2026 and 青空えいご on October 31, 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.*