# Call by Color 36 vs Greatest Common Factor

The clearest difference is update cadence: Call by Color 36 at every 4 months against Greatest Common Factor's every 38 months. Greatest Common Factor's advantage is device support (3 vs 1) and iOS requirement (14.1 vs 18.5). On price, ads, in-app purchases and monetization model there is nothing between them.

Call by Color 36 costs $0.99 and Greatest Common Factor $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Call by Color 36 ships an update every 4 months, Greatest Common Factor every 38 months. Both last shipped on November 3, 2026.

## The numbers

| Metric | Call by Color 36 | Greatest Common Factor |
| --- | --- | --- |
| Price | $0.99 | $0.99 |
| Rating | — | **[5.0 (1 ratings)](https://appshunter.io/ios/app/greatest-common-factor/id1573121817/reviews)** |
| Number of ratings | — | **1** |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 4 months** | Every 38 months |
| Monetization | Paid | Paid |
| Size | 1 MB | 1 MB |
| Requires iOS | 18.5 | **14.1** |
| Devices | iPhone | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Andreas Vogel](https://appshunter.io/developer/889323201) | [H Valeur](https://appshunter.io/developer/621824042) |

## What reviewers say

### Call by Color 36

[App page](https://appshunter.io/ios/app/call-by-color-36/id1494633758)

Quickly call your most important contacts with a single tap. Store up to 36 phone numbers on customizable tiles, organized across three screens. Personalize the look with colors and adjust font sizes for better readability.

**Highlights:** Up to 36 phone numbers, 12 tiles on three screens, Customizable font size, Screen color customization, Dark mode support, Tap to call functionality, No ads

**Features:** Vision Pro support

**In-app purchases:** none


### Greatest Common Factor

[App page](https://appshunter.io/ios/app/greatest-common-factor/id1573121817)

This app helps users find the factors of numbers, calculate the Greatest Common Factor (GCF) for two or more numbers, and simplify fractions. It's a useful tool for understanding number theory concepts and performing fraction simplification.

**Highlights:** Find factors of a number, Calculate GCF of two or more numbers, Simplify fractions, Understand number theory concepts, Fraction simplification tool

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

**In-app purchases:** none


## Frequently asked questions

### Is Call by Color 36 free?

Call by Color 36 costs $0.99, with no in-app purchases.

### Is Greatest Common Factor free?

Greatest Common Factor costs $0.99, with no in-app purchases.

### Do Call by Color 36 or Greatest Common Factor have ads?

Neither Call by Color 36 nor Greatest Common Factor shows ads.

### Which is updated more often, Call by Color 36 or Greatest Common Factor?

Call by Color 36 ships an update every 4 months, and Greatest Common Factor every 38 months. Most recently, Call by Color 36 was updated on November 3, 2026 and Greatest Common Factor on November 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.*