просто́й
prostój
The English word 'prime' is translated into Russian as просто́й (prostój) in a mathematical context.
In mathematics, просто́й is an adjective used to describe a number that has no factors except itself and unity. Note that просто́й is a homonym. Outside of a mathematical context, it can also mean 'simple' or 'plain'.
Meaning: mathematics: having no factors except itself and unity (adj)
Which one should you use?
While просто́й is the adjective for 'prime', if you want to specifically refer to a 'prime number', the standard way to say this is the noun phrase просто́е число́.
Related words
How does it change in a sentence?
The adjective просто́й is used to modify a noun, but for the specific mathematical concept of a 'prime number', the phrase просто́е число́ is used.
How do you pronounce it?
prostój
Did you know?
- While English uses 'prime' to mean 'first in importance' or 'best', the Russian просто́й never carries this meaning of superiority.
- The word просто́й is used both to describe a 'prime number' and to describe a person who is 'simple-minded' or 'naive'.
- The term for 'composite number' in Russian is составно́е число́, which literally translates to a 'composed number' or 'compound number'.
Examples in context
- Простое числоPrime number
- Простой факторPrime factor
Example conversation
Dmitry and Olga are studying mathematics together.
- Дмитрий DmitryО́льга, девя́ть э́то просто́й число́?Olga, devyat' eto prostoy chislo?Olga, is nine a prime number?
- Ольга OlgaНет, оно́ дели́тся на три́.Net, ono delitsya na tri.No, it is divisible by three.
- Дмитрий DmitryА оди́ннадцать просто́й?A odinnadtsat' prostoy?And is eleven prime?
- Ольга OlgaДа, оди́ннадцать э́то просто́й число́.Da, odinnadtsat' eto prostoy chislo.Yes, eleven is a prime number.
Sources
- Wiktionary, “prime” translations, CC BY-SA 4.0, dump of 2026-09-26.
