399
399 BC is the year Socrates was executed.
- Odd
- Composite
Where 399 fits
Why 399 is special
He was convicted of impiety and corrupting the young, and could have gone into exile. Choosing to accept the sentence is the act that made him a philosophical figure rather than a defendant.
Factors & digit properties
- Divisors (8)
- 1, 3, 7, 19, 21, 57, 133, 399
- Prime factorisation
- 3 × 7 × 19
- Digit sum
- 21
- Digital root
- 3
Representations
- Decimal
- 399
- Binary
- 110001111
- Octal
- 617
- Hexadecimal
- 18f
- Roman numeral
- CCCXCIX
- Scientific notation
- 3.990 × 10^2
Other mathematical patterns
- Deficient number
- Harshad (Niven) number
- Lucky number (mathematical sieve)
Related numbers & connections
Socrates was executed in 399 BC and Alexander died in 323. Aristotle taught Alexander and had been taught by Plato, who was taught by Socrates — four generations linking a trial to an empire.
View 323 →Other connections
- is associated with323
why?
Strength 0.50, confidence "high".
History
Socrates was offered exile and declined it, arguing that a citizen who accepts a city's benefits cannot reject its judgements selectively. Everything known about him comes from students, chiefly Plato.
DocumentedHistoryGeography: AthensPeriod: 399 BC
Common questions
Is 399 a prime number?
No, 399 is not prime.
What are the factors of 399?
The factors of 399 are 1, 3, 7, 19, 21, 57, 133, 399.
What is 399 in Roman numerals?
399 in Roman numerals is CCCXCIX.
About this page's data
Mathematical facts:computed directly from the number's value — nothing to source or verify externally.
Contextual records: 1 reviewer-confirmed record, sourced and reviewed before publication.
Last reviewed: 3 August 2026