Number reference
199 explained.
199: one hundred ninety-nine, prime; factors, prime factorization, roots, binary, hexadecimal, and digit properties.
Identity and representations
- Written form
- one hundred ninety-nine
- Classification
- prime
- Factors
- 1, 199
- Prime factorization
- 199
- Square root
- 14.106736
- Cube root
- 5.838272
- Binary
- 11000111
- Octal
- 307
- Hexadecimal
- C7
- Roman numeral
- CXCIX
- Digit sum
- 19
- Digital root
- 1
What makes 199 notable
- Prime. 199 is prime: it has exactly two divisors, 1 and itself, so it cannot be split into equal whole-number groups any other way.
199 in everyday use
One hundred ninety-nine is the largest prime below 200 and the closing member of the quadruplet 191, 193, 197, 199. It is also a permutable prime: every rearrangement of its digits, 199, 919, and 991, is prime. Only a handful of permutable primes with distinct digits are known — 13, 17, 37, 79, 113, 199, and 337 among them — and it is believed there are no more beyond 991 apart from repunit primes made entirely of ones.
In commerce the number is everywhere as the price ending .99, a practice known as charm pricing: 1.99 or 199 reads as noticeably cheaper than 2.00 or 200 even though the difference is a single unit. Studies of shopping behaviour have repeatedly found the effect is real, if modest. Mathematically 199 is the 46th prime, its digit sum is 19, and it is one less than 200, so it is the last odd number before the round figure.
Nearby numbers
How to read this page
Because 199 is prime, the factor list stops at 1 and 199 itself, so it cannot be shared into equal whole-number groups. That is also what makes it useful as a building block: every larger number with 199 in its prime factorisation inherits it from here.
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