16
16 is a composite number, even, a calendar year.
16 (sixteen) is an even 2-digit number. It is a composite number with 5 divisors, and factors as 2⁴. It is a perfect square (4²) and a power of two (2⁴). Written other ways, in Roman numerals it is XVI and in binary, 10000.
Interestingness
Historical context — 16 AD
Calendar year
AD 16 (XVI) was a leap year starting on Wednesday of the Julian calendar.
Excerpt from Wikipedia (en) ↗ · Licensed CC BY-SA 4.0 Read the full article on Wikipedia →
Historical context — 16 BC
Calendar year
Year 16 BC was either a common year starting on Monday, Tuesday or Wednesday or a leap year starting on Monday or Tuesday of the Julian calendar and a common year starting on Sunday of the Proleptic Julian calendar.
Excerpt from Wikipedia (en) ↗ · Licensed CC BY-SA 4.0 Read the full article on Wikipedia →
Year facts
- Year type
-
Leap year
Divisible by 4 and not by 100; February has 29 days.
- Days in year
- 366
- ISO weeks
- 52
- Started on
-
Friday
January 1, 16
- Ended on
-
Saturday
December 31, 16
- Friday the 13ths
-
1
One Friday the 13th this year.
- Decade
-
10s
10–19
- Century
-
1st century
1–100
- Millennium
-
1st millennium
1–1000
- Years ago
-
2,010
2010 years before 2026.
In other calendars
- Hebrew
-
3776 / 3777 AM
Rosh Hashanah falls in September/October.
- Chinese
-
Year of the zodiac:Fire zodiac:Rat
Sexagenary cycle position 13 of 60. Lunar new year falls in late January / mid-February.
- Buddhist Era
-
559 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Ethiopian
-
8 / 9 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
-62 / -63 Saka
Indian national calendar; year starts in March.
Properties
- Parity
- Even
- Digit count
- 2
- Digit sum
- 7
- Digit product
- 6
- Digital root
- 7
- Palindrome
- No
- Bit width
- 5 bits
- Reversed
- 61
- Flips to (rotate 180°)
- 91
- Recamán's sequence
- a(27) = 16
- Square (n²)
- 256
- Cube (n³)
- 4,096
- Square root (√n)
- 4
- Divisor count
- 5
- σ(n) — sum of divisors
- 31
- φ(n) — Euler's totient
- 8
- Sum of prime factors
- 8
Primality
Prime factorization: 2 4
Divisors & multiples
Sums & aliquot sequence
Representations
- In words
- sixteen
- Ordinal
- 16th
- Roman numeral
- XVI
- Binary
- 10000
- Octal
- 20
- Hexadecimal
- 0x10
- Base64
- EA==
- One's complement
- 239 (8-bit)
- Scientific notation
- 1.6 × 10¹
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒌋𒁹𒁹𒁹𒁹𒁹𒁹
- Egyptian hieroglyphic
- 𓎆𓏺𓏺𓏺𓏺𓏺𓏺
- Greek (Milesian)
- ιϛʹ
- Mayan (base 20)
- 𝋰
- Chinese
- 一十六
- Chinese (financial)
- 壹拾陸
Digit at this position in famous constants
- π — Pi (π)
- Digit 16 = 3
- e — Euler's number (e)
- Digit 16 = 5
- φ — Golden ratio (φ)
- Digit 16 = 4
- √2 — Pythagoras's (√2)
- Digit 16 = 5
- ln 2 — Natural log of 2
- Digit 16 = 5
- γ — Euler-Mascheroni (γ)
- Digit 16 = 2
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 16, here are decompositions:
- 3 + 13 = 16
- 5 + 11 = 16
As an ASCII codepoint, 16 is control character (0x10). ASCII control character.
As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.16.
- Address
- 0.0.0.16
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.0.16
Unspecified address (0.0.0.0/8) — "this network" placeholder.
Matches numbered highway designation:
- I-16 — Macon to Savannah, GA.
Heard as a frequency, 16 Hz is closest to:
- Concert pitch (A4 = 440 Hz): C0 (16.4 Hz, -38¢)
- Scientific pitch (C4 = 256 Hz): C0 (16 Hz, exact)
- Baroque pitch (A4 = 415 Hz): C♯0 (16.3 Hz, -36¢)
As a MIDI note number, 16 is E0 (20.6 Hz at concert pitch). (very low — many laptop and phone speakers can't reproduce it)
On the periodic table, atomic number 16 is Sulfur (S) — period 3.
Related reading
- Egyptian hieroglyphic numerals — Seven hieroglyphs for every power of ten, from a single stroke to a million.