# Prime Factors

> Interactive tool for exploring prime numbers and their factors up to one trillion. (iPhone/iPad app by Paul Hangas.)

- Source: https://appshunter.io/ios/app/prime-factors/id741746948 (this page in markdown: same URL + `.md`)
- Developer: [Paul Hangas](https://appshunter.io/developer/433121902)
- Category: Education
- Price: $0.99
- Rating: 3.90/5 from 24 App Store ratings · 28 written reviews indexed
- Age rating: 4+
- Requires: iOS 18.0 · 1 MB
- Languages: American English
- Released: 2013-11-22
- Data updated: 2026-09-02
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/prime-factors/id741746948/reviews.md

## What is Prime Factors?

View all numbers from 1 to 1,000,000,000,000.  Prime numbers shown with a red circle.  Tap a number to see its Prime Factors.  Jump directly to a number with the search field.

• Prime Numbers are marked with a red circle
• Prime Factors can be viewed by tapping on a number
• Pinch and Zoom to change the number of columns

## Key features

- View numbers up to 1 trillion
- Prime numbers highlighted
- Tap for prime factors
- Search for specific numbers
- Pinch and zoom display

## Recent user reviews (10 of 28)

All indexed reviews: https://appshunter.io/ios/app/prime-factors/id741746948/reviews.md

### 5/5 — Beautiful app, so happy it’s working again

*2025-09-06*

This is a beautiful, elegant, and useful app, one of my favorite math apps to use. I was very sad when it stopped working sometime last year, but now it’s been updated and it’s working again. I haven’t found another prime factorization app anywhere near as satisfying to use, so I’m very happy it’s back.

### 1/5 — Beautiful app, but has stopped working

*2025-07-06*

This was a beautiful, elegant, and useful app, one of my favorite math apps to use. But it stopped working a while ago. You can still scroll through all the numbers and see which are prime, but you can’t search for specific numbers any more and the app won’t give you the prime factors for any number any more. I hope this is updated before long! I haven’t found another prime factorization app anywhere near as satisfying to use.

### 2/5 — Accessibility

*2025-05-12, version 2.5*

It’s been brilliant but just recently I can’t access the app’s functions at all! I’ve tried reloading it, etc, but to no avail! I love this usually!

### 5/5 — The best for me

*2025-03-06*

Edit: this app quite working a few months ago after ios18 updates. Still shows primes but doesn’t show factors of other numbers when you click on them.  

Really loved this app before. 

This app is perfect for me, I’m always jotting numbers down for patterns and god knows what. Big problem tho. It quite working after ios18 update. Please fix asap.

### 1/5 — No longer works

*2025-02-09*

App only identifies prime numbers in red but does not give the prime factors of the nonprime numbers.

### 5/5 — Greatest App in Apple’s AppStore

*2025-01-17, version 2.5*

I have used this app daily for at least 8 yrs while searching for new primes to use in divining the wisdom of ancient Babylon and even further beyond. 
Paul Hangas is brilliant and adventurous mind, Kudos to you!

### 5/5 — The best for me

*2024-12-17*

This app is perfect for me, I’m always jotting numbers down for patterns and god knows what. Big problem tho. It quite working after ios18 update. Please fix asap.

### 1/5 — Dec 2024. App does not work

*2024-12-07*

When I try to press a number absolutely nothing works, and this is across all of my iPads. I think this app is completely broken. Do not download until the developer has updated it.

### 5/5 — Problem with app

*2024-11-23*

Paul, as of this morning, Prime Factors stopped displaying factors. 

Are you able to update it?

Thank you kindly.

### 1/5 — Not working

*2024-10-29*

When I click on a number nothing happens. I can’t see properties. Fraud app. Spam

## Frequently asked questions about Prime Factors

### What does this app do?

This app allows you to explore numbers from 1 up to one trillion. It visually highlights prime numbers with a red circle and lets you tap any number to see its prime factors. You can also search for specific numbers and adjust the display using pinch and zoom.

### How do I find the prime factors of a number?

To find the prime factors of a number, simply tap on that number within the app's interface. The app will then display its prime factorization. This feature is available for all numbers within the displayed range.

### Is this app free to use?

Yes, this app is completely free to use. There are no costs associated with downloading or using its features. It does not contain in-app purchases or advertisements.

### What is the maximum number I can explore?

You can explore numbers all the way up to one trillion (1,000,000,000,000) within this application. This extensive range allows for deep exploration of number properties.

### Who would benefit from using this app?

This app is beneficial for students learning about prime numbers and factorization, educators teaching mathematics, and anyone with an interest in number theory. Its interactive nature makes it a valuable learning tool.

## Version history (last 5 releases)

### 3.0 — 2025-08-19

• Updated for latest iOS and iPadOS.
• Removed advertisements.
• Bug fixes.

### 2.5 — 2020-11-24

Updates for iOS 14.  Now able to view numbers from 1 to 1,000,000,000,000.

### 2.1 — 2020-08-16

Tapping a prime number will now show the that is the nth prime number.

### 2.0 — 2020-05-12

Updated for latest devices, and added support for dark mode.

### 1.1.1 — 2017-01-16

Updates for iOS 10

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## More apps by Paul Hangas

- [TapTapBlocks](https://appshunter.io/ios/app/taptapblocks/id433121899)
- [Think 3D Pro](https://appshunter.io/ios/app/think-3d-pro/id446608416)
- [Think 3D](https://appshunter.io/ios/app/think-3d/id463364378)
- [Unfold](https://appshunter.io/ios/app/unfold/id557099803)
- [Bottles - Wine Cellar Manager](https://appshunter.io/ios/app/bottles-wine-cellar-manager/id953817122)

All apps by Paul Hangas: https://appshunter.io/developer/433121902

## Related topics

[prime numbers](https://appshunter.io/ios/topics/prime-numbers)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-09-02.*