Number

101

101 is a prime, odd, a calendar year.

Arithmetic Number Chen Prime Consecutive Digits Cousin Prime Deficient Number Evil Number Flippable Palindrome Prime Pythagorean Prime Recamán's Sequence Sexy Prime Squarefree Strobogrammatic Twin Prime Year

Historical context — 101 AD

Calendar year

Year 101 (CI) was a common year starting on Friday of the Julian calendar.

Excerpt from Wikipedia (en) ↗ · Licensed CC BY-SA 4.0 · English fallback Read the full article on Wikipedia →

Historical context — 101 BC

Calendar year

Year 101 BC was a year of the pre-Julian Roman calendar.

Excerpt from Wikipedia (en) ↗ · Licensed CC BY-SA 4.0 · English fallback Read the full article on Wikipedia →

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: Saturday
January 1, 101
Ended on: Saturday
December 31, 101
Friday the 13ths: 1
One Friday the 13th this year.
Decade: 100s
100–109
Century: 2nd century
101–200
Millennium: 1st millennium
1–1000
Years ago: 1,925
1925 years before 2026.

In other calendars

Hebrew: 3861 / 3862 AM
Rosh Hashanah falls in September/October.
Chinese: Year of the zodiac:Metal zodiac:Ox
Sexagenary cycle position 38 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 644 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Ethiopian: 93 / 94 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 23 / 22 Saka
Indian national calendar; year starts in March.

Properties

Parity: Odd
Digit count: 3
Digit sum: 2
Digit product: 0
Digital root: 2
Palindrome: Yes
Bit width: 7 bits
Recamán's sequence: a(385) = 101
Square (n²): 10,201
Cube (n³): 1,030,301
Divisor count: 2
σ(n) — sum of divisors: 102
φ(n) — Euler's totient: 100

Primality

101 is prime. It has exactly two divisors: 1 and itself.

Divisors & multiples

All divisors (2)

1 · 101

Aliquot sum (sum of proper divisors): 1

Factor pairs (a × b = 101)

1 × 101

First multiples

101 · 202 (double) · 303 · 404 · 505 · 606 · 707 · 808 · 909 · 1,010

Sums & aliquot sequence

As a sum of two squares: 1² + 10²

As consecutive integers: 50 + 51

Representations

In words: one hundred one
Ordinal: 101st
Roman numeral: CI
Binary: 1100101
Octal: 145
Hexadecimal: 0x65
Base64: ZQ==
One's complement: 154 (8-bit)

In other bases

ternary (3) 10202

quaternary (4) 1211

quinary (5) 401

senary (6) 245

septenary (7) 203

nonary (9) 122

undecimal (11) 92

duodecimal (12) 85

tridecimal (13) 7a

tetradecimal (14) 73

pentadecimal (15) 6b

Historical numeral systems

Babylonian (base 60): 𒁹 𒌋𒌋𒌋𒌋𒁹
Egyptian hieroglyphic: 𓍢𓏺
Greek (Milesian): ραʹ
Mayan (base 20): 𝋥·𝋡
Chinese: 一百零一
Chinese (financial): 壹佰零壹

In other modern scripts

Eastern Arabic ١٠١ Devanagari १०१ Bengali ১০১ Tamil ௧௦௧ Thai ๑๐๑ Tibetan ༡༠༡ Khmer ១០១ Lao ໑໐໑ Burmese ၁၀၁

Digit at this position in famous constants

π — Pi (π): Digit 101 = 9
e — Euler's number (e): Digit 101 = 4
φ — Golden ratio (φ): Digit 101 = 4
√2 — Pythagoras's (√2): Digit 101 = 7
ln 2 — Natural log of 2: Digit 101 = 5
γ — Euler-Mascheroni (γ): Digit 101 = 5

Also seen as

Prime neighborhood

Adjacent primes:

Previous prime: 97 (gap of 4)
Next prime: 103 (gap of 2)

Pair status: twin with 103, cousin with 97.

ASCII character

As an ASCII codepoint, 101 is e. Printable ASCII character e.

HTTP status code

HTTP 101 Switching Protocols — Server is switching protocols at the client's request (e.g., to WebSocket).

1xx class: Informational.

Hex color

#000065

RGB(0, 0, 101)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.101.

Address: 0.0.0.101
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.0.101

Unspecified address (0.0.0.0/8) — "this network" placeholder.

US numbered highway

Matches numbered highway designation:

US 101 — Tumwater, WA to Los Angeles, CA — the Pacific Coast highway.

US 101 on Wikipedia ↗