Is it Prime? vs Momentous Clock
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Is it Prime?
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.
- Prime number identification
- Simple number input
- Instant yes/no results
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This application serves only one function - to satisfy your curiosity when you wonder whether a given number is prime or not. You put in the number, it says yes or no. Really, that's all it does.
Momentous Clock
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.
- 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
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Time isn’t just 6:31. It’s 631 - a prime! A lucky prime... It’s the combination to the bike lock you had as a kid. It might be the last digits of the cell phone of someone you love. This is a clock for people who notice things like that. Every minute, it: • Computes mathematical properties of the current time • Surfaces number theory facts (prime, factorization, powers, sequences, curiosities) • Scrambles them onto glowing 16-segment LED displays, like your old Speak 'n Spell • Optionally finds personal number connections in your contacts — entirely on device Works great as a Mac app via Catalyst. Contact matching happens entirely on device. No personal data is ever transmitted. Usage analytics (anonymous) are collected to improve the app. If you’ve ever factored timestamps in your head, smiled at 5:12 = 2⁹, or paused at 17:29… This is the clock for you. Make every minute momentous.
Screenshots
Verdict
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.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
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.
| Parameter | Is it Prime? | Momentous Clock |
|---|---|---|
| Price | Free | Free |
| Rating | 3.2 (5 ratings) | 5.0 (2 ratings) — better |
| Positive reviews | 71.4% of reviews | — |
| Number of ratings | 5 — better | 2 |
| Update frequency | Every 74 months | Every 6 days — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 15.0 — better | 15.1 |
| Further details — not scored | ||
| Size | 1 MB | 24 MB |
| Age rating | 4+ | 4+ |
| Developer | Wismar | Tutukain Software, LLC |
Customer experience
Is it Prime?
Momentous Clock
In-app purchases
Is it Prime?
No in-app purchases
Momentous Clock
No in-app purchases
Questions
Is Is it Prime? free?
Is Momentous Clock free?
Which has better reviews, Is it Prime? or Momentous Clock?
Do Is it Prime? or Momentous Clock have ads?
Which is updated more often, Is it Prime? or Momentous Clock?
Other comparisons
