Number

421

421 is a prime, odd, a calendar year.

Arithmetic Number Deficient Number Descending Digits Odious Number Pernicious Number Prime Pythagorean Prime Recamán's Sequence Squarefree Twin Prime Year

Historical context — 421 AD

Calendar year

Year 421 (CDXXI) was a common year starting on Saturday of the Julian calendar.

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Historical context — 421 BC

Calendar year

Year 421 BC was a year of the pre-Julian Roman calendar.

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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, 421
Ended on: Friday
December 31, 421
Friday the 13ths: 1
One Friday the 13th this year.
Decade: 420s
420–429
Century: 5th century
401–500
Millennium: 1st millennium
1–1000
Years ago: 1,605
1605 years before 2026.

In other calendars

Hebrew: 4181 / 4182 AM
Rosh Hashanah falls in September/October.
Chinese: Year of the zodiac:Metal zodiac:Rooster
Sexagenary cycle position 58 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 964 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Ethiopian: 413 / 414 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 343 / 342 Saka
Indian national calendar; year starts in March.

Properties

Parity: Odd
Digit count: 3
Digit sum: 7
Digit product: 8
Digital root: 7
Palindrome: No
Bit width: 9 bits
Reversed: 124
Recamán's sequence: a(474) = 421
Square (n²): 177,241
Cube (n³): 74,618,461
Divisor count: 2
σ(n) — sum of divisors: 422
φ(n) — Euler's totient: 420

Primality

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

Divisors & multiples

All divisors (2)

1 · 421

Aliquot sum (sum of proper divisors): 1

Factor pairs (a × b = 421)

1 × 421

First multiples

421 · 842 (double) · 1,263 · 1,684 · 2,105 · 2,526 · 2,947 · 3,368 · 3,789 · 4,210

Sums & aliquot sequence

As a sum of two squares: 14² + 15²

As consecutive integers: 210 + 211

Representations

In words: four hundred twenty-one
Ordinal: 421st
Roman numeral: CDXXI
Binary: 110100101
Octal: 645
Hexadecimal: 0x1A5
Base64: AaU=
One's complement: 65,114 (16-bit)

In other bases

ternary (3) 120121

quaternary (4) 12211

quinary (5) 3141

senary (6) 1541

septenary (7) 1141

nonary (9) 517

undecimal (11) 353

duodecimal (12) 2b1

tridecimal (13) 265

tetradecimal (14) 221

pentadecimal (15) 1d1

Historical numeral systems

Babylonian (base 60): 𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒁹
Egyptian hieroglyphic: 𓍢𓍢𓍢𓍢𓎆𓎆𓏺
Greek (Milesian): υκαʹ
Mayan (base 20): 𝋡·𝋡·𝋡
Chinese: 四百二十一
Chinese (financial): 肆佰貳拾壹

In other modern scripts

Eastern Arabic ٤٢١ Devanagari ४२१ Bengali ৪২১ Tamil ௪௨௧ Thai ๔๒๑ Tibetan ༤༢༡ Khmer ៤២១ Lao ໔໒໑ Burmese ၄၂၁

Digit at this position in famous constants

π — Pi (π): Digit 421 = 3
e — Euler's number (e): Digit 421 = 7
φ — Golden ratio (φ): Digit 421 = 9
√2 — Pythagoras's (√2): Digit 421 = 5
ln 2 — Natural log of 2: Digit 421 = 2
γ — Euler-Mascheroni (γ): Digit 421 = 9

Also seen as

Prime neighborhood

Adjacent primes:

Previous prime: 419 (gap of 2)
Next prime: 431 (gap of 10)

Pair status: twin with 419.

Unicode codepoint

Latin Small Letter P With Hook

U+01A5

Lowercase letter (Ll)

UTF-8 encoding: C6 A5 (2 bytes).

Lookup U+01A5 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#0001A5

RGB(0, 1, 165)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.1.165.

Address: 0.0.1.165
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.1.165

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