isPrime? vs Eternal Clock
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
isPrime?
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It's a fast prime number checker.
Eternal Clock
A minimalist digital clock that displays the time with no distractions. It offers a clean interface with subtle visual cues like a sun, moon, or mealtime hints, all without ads, data collection, or notifications.
- Ad-free experience
- No data collection
- No push notifications
- Minimalist interface
- Subtle visual cues (sun, moon, food)
- No settings or permissions required
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A pure digital clock. Nothing more, nothing less. It does one thing perfectly: shows the time. - No ads - No data collection - No push notifications - No permissions - Not even settings Sometimes a sun, sometimes a moon. At mealtimes, a playful hint of food. Still, nothing more than time — free from risks, interruptions, or hidden fees.
Screenshots
Verdict
The clearest difference is update cadence: isPrime? at daily against Eternal Clock's weekly. Eternal Clock's advantage is iOS requirement (12.0 vs 15.0). On price, ads, in-app purchases and device support 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.
isPrime? ships an update daily, Eternal Clock weekly. The most recent releases landed on September 20, 2026 and September 17, 2026 respectively.
| Parameter | isPrime? | Eternal Clock |
|---|---|---|
| Price | Free | Free |
| Rating | — | 5.0 (1 ratings) — better |
| Number of ratings | — | 1 — better |
| Update frequency | Daily — better | Weekly |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | — | Free |
| Devices | iPhone, iPod | iPhone, iPad, iPod — better |
| Requires iOS | 15.0 | 12.0 — better |
| Further details — not scored | ||
| Size | 0 MB | 23 MB |
| Age rating | 4+ | 4+ |
| Developer | Omer Faruk Mesebuken | Daehyeon Shin |
In-app purchases
isPrime?
No in-app purchases
Eternal Clock
No in-app purchases
Questions
Is isPrime? free?
Is Eternal Clock free?
Do isPrime? or Eternal Clock have ads?
Which is updated more often, isPrime? or Eternal Clock?
Other comparisons
