100
100 is a composite number, even, a calendar year.
One hundred is the square of 10 and the basis of percentages. It marks a natural milestone in many counting and measurement systems.
Notable events — 100 AD
- Undated Emperor Trajan and Frontinus serve as Roman consuls; brick becomes a primary Roman building material.
Events compiled from Wikipedia ↗ · Licensed CC BY-SA 4.0
Notable events — 100 BC
- Jul 12 Traditional birth date of Julius Caesar.
Events compiled from Wikipedia ↗ · Licensed CC BY-SA 4.0
Year facts
- Year type
-
Common year
Standard 365-day year; not divisible by 4 (or divisible by 100 but not 400).
- Days in year
- 365
- ISO weeks
- 52
- Started on
-
Friday
January 1, 100
- Ended on
-
Friday
December 31, 100
- Friday the 13ths
-
1
One Friday the 13th this year.
- Decade
-
100s
100–109
- Century
-
1st century
1–100
- Millennium
-
1st millennium
1–1000
- Years ago
-
1,926
1926 years before 2026.
In other calendars
- Hebrew
-
3860 / 3861 AM
Rosh Hashanah falls in September/October.
- Chinese
-
Year of the zodiac:Metal zodiac:Rat
Sexagenary cycle position 37 of 60. Lunar new year falls in late January / mid-February.
- Buddhist Era
-
643 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Ethiopian
-
92 / 93 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
22 / 21 Saka
Indian national calendar; year starts in March.
Cultural significance
Basis of percentages; "a centenarian" lives 100 years; a perfect score.
Ten squared — completion in decimal.
Sourced from Wikipedia (Numerology, Chinese numerology, Gematria, and per-culture articles).
Properties
- Parity
- Even
- Digit count
- 3
- Digit sum
- 1
- Digit product
- 0
- Digital root
- 1
- Palindrome
- No
- Bit width
- 7 bits
- Reversed
- 1
- Flips to (rotate 180°)
- 1
- Recamán's sequence
- a(387) = 100
- Square (n²)
- 10,000
- Cube (n³)
- 1,000,000
- Square root (√n)
- 10
- Divisor count
- 9
- σ(n) — sum of divisors
- 217
- φ(n) — Euler's totient
- 40
- Sum of prime factors
- 14
Primality
Prime factorization: 2 2 × 5 2
Divisors & multiples
Sums & aliquot sequence
Representations
- In words
- one hundred
- Ordinal
- 100th
- Roman numeral
- C
- Binary
- 1100100
- Octal
- 144
- Hexadecimal
- 0x64
- Base64
- ZA==
- One's complement
- 155 (8-bit)
Historical numeral systems
- Babylonian (base 60)
- 𒁹 𒌋𒌋𒌋𒌋
- Egyptian hieroglyphic
- 𓍢
- Greek (Milesian)
- ρʹ
- Mayan (base 20)
- 𝋥·𝋠
- Chinese
- 一百
- Chinese (financial)
- 壹佰
Digit at this position in famous constants
- π — Pi (π)
- Digit 100 = 7
- e — Euler's number (e)
- Digit 100 = 7
- φ — Golden ratio (φ)
- Digit 100 = 7
- √2 — Pythagoras's (√2)
- Digit 100 = 2
- ln 2 — Natural log of 2
- Digit 100 = 7
- γ — Euler-Mascheroni (γ)
- Digit 100 = 9
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 100, here are decompositions:
- 3 + 97 = 100
- 11 + 89 = 100
- 17 + 83 = 100
- 29 + 71 = 100
- 41 + 59 = 100
- 47 + 53 = 100
As an ASCII codepoint, 100 is d. Printable ASCII character d.
HTTP 100 Continue — Server has received the request headers; client should continue with the body.
1xx class: Informational.
As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.100.
- Address
- 0.0.0.100
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.0.100
Unspecified address (0.0.0.0/8) — "this network" placeholder.