# Is it Prime? vs Momentous Clock

The clearest difference is rating: Momentous Clock at 5.0 against Is it Prime?'s 3.2. Momentous Clock also leads on update cadence (every 6 days vs every 74 months). On price, ratings volume, ads and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Momentous Clock holds the better App Store score, 5.0 against 3.2. Both are backed by a comparable volume of ratings — 5 and 2 respectively.

Is it Prime? ships an update every 74 months, Momentous Clock every 6 days. The most recent releases landed on October 23, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | Is it Prime? | Momentous Clock |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [3.2 (5 ratings)](https://appshunter.io/ios/app/is-it-prime/id326095651/reviews) | **[5.0 (2 ratings)](https://appshunter.io/ios/app/momentous-clock/id1608715857/reviews)** |
| Number of ratings | **5** | 2 |
| Positive reviews | 71.4% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 74 months | **Every 6 days** |
| Monetization | Free | Free |
| Size | 1 MB | 24 MB |
| Requires iOS | **15.0** | 15.1 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Wismar](https://appshunter.io/developer/307757950) | [Tutukain Software, LLC](https://appshunter.io/developer/1608715859) |

## What reviewers say

### Is it Prime?

[App page](https://appshunter.io/ios/app/is-it-prime/id326095651)

Enter any number to instantly determine if it is a prime number or not. This straightforward utility provides a quick answer to your mathematical curiosity.

**Highlights:** Prime number identification, Simple number input, Instant yes/no results

**Features:** macOS Compatibility

**In-app purchases:** none


### Momentous Clock

[App page](https://appshunter.io/ios/app/momentous-clock/id1608715857)

This app transforms your device's clock into a dynamic display of mathematical properties and number theory facts for the current time. It optionally reveals personal number connections from your contacts, all processed securely on your device.

**Highlights:** Computes mathematical properties of time, Surfaces number theory facts, Displays time on 16-segment LED screens, Finds personal number connections in contacts, On-device contact matching, Works via Catalyst on Mac

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Is it Prime? free?

Is it Prime? is free to download, with no in-app purchases.

### Is Momentous Clock free?

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

### Which has better reviews, Is it Prime? or Momentous Clock?

Momentous Clock is rated higher. Is it Prime? averages 3.2 out of 5 from 5 ratings, while Momentous Clock averages 5.0 from 2 ratings.

### Do Is it Prime? or Momentous Clock have ads?

Neither Is it Prime? nor Momentous Clock shows ads.

### Which is updated more often, Is it Prime? or Momentous Clock?

Is it Prime? ships an update every 74 months, and Momentous Clock every 6 days. Most recently, Is it Prime? was updated on October 23, 2026 and Momentous Clock on October 24, 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.*