PrimeCalc vs Primality
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
PrimeCalc
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--- PrimeCalc feature --- ■ Normal arithmetic operation (×, /, +, -) is available. ■ prime: integer calculation (Division remainder ÷, prime factorization p) can be done. (You can also exponentiate.) ■ auto: Automatic calculation, memory storage, history recording is possible. ■ global: Digit display of countries around the world is possible. （千、万、億、兆、京、垓、・・・） ■ iPhone / iPad is available. Free. We are displaying advertisements. Caution) In case of large number, calculation error etc. may occur. Please use it together with other calculator. If you have comments, questions, etc., please email or bulletin board. http: //www.eonet.ne.jp/~treechart/
Primality
This app determines if a given integer is prime or provides its prime factors. It also calculates the ordinal position of prime numbers found, up to a certain limit.
- Primality testing
- Prime factorization
- Prime ordinality calculation
- Large integer support (up to 999,999,999,999)
- Clean and simple interface
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The Primality App has a clean and simple, yet powerful, function: Given any integer, the app determines either that the given integer is prime or else it provides all prime factors of that integer. Very clean, very simple, focussed. The app operates in the range of 0 - 999,999,999,999. A popular feature of the app is its ability to determine the prime ordinality of each prime found, such as observing that 97 if the 25th prime. (However, this particular feature is available only up to the 100,000th prime, which is 1,299,709.) Requires iOS 13 or higher.
Screenshots
Verdict
The clearest difference is ads: Primality at none against PrimeCalc's shown. On price, update cadence, 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.
PrimeCalc ships an update every 5 weeks, Primality every 2 months. The most recent releases landed on September 10, 2026 and September 9, 2026 respectively.
| Parameter | PrimeCalc | Primality |
|---|---|---|
| Price | Free | Free |
| Rating | — | 4.9 (24 ratings) — better |
| Positive reviews | — | 100.0% of reviews |
| Number of ratings | — | 24 — better |
| Update frequency | Every 5 weeks — better | Every 2 months |
| Ads | Yes | No — better |
| In-app purchases | No | No |
| Monetization | — | Free |
| Devices | iPhone, iPad, iPod — better | iPhone, iPod |
| Requires iOS | 12.0 — better | 13.2 |
| Further details — not scored | ||
| Size | 12 MB | 1 MB |
| Age rating | 4+ | 4+ |
| Developer | Yutaka Nakao | Bruce Schechter |
In-app purchases
PrimeCalc
No in-app purchases
Primality
No in-app purchases
