Number

408

408 is a composite number, even, a calendar year.

408 (four hundred eight) is an even 3-digit number. It is a composite number with 16 divisors, and factors as 2³ × 3 × 17. Its proper divisors sum to 672, more than the number itself, making it an abundant number. Written other ways, in Roman numerals it is CDVIII and in binary, 110011000.

Abundant Number Evil Number Harshad / Niven Octagonal Pell Number Practical Number Recamán's Sequence Semiperfect Number Year

Interestingness

★ ★ ★ ★ ☆

6 notable facts · grade B

396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420

less more

Historical context — 408 AD

Calendar year

Year 408 (CDVIII) 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 — 408 BC

Calendar year

Year 408 BC was a year of the pre-Julian Roman 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: Tuesday
January 1, 408
Ended on: Wednesday
December 31, 408
Friday the 13ths: 1
One Friday the 13th this year.
Decade: 400s
400–409
Century: 5th century
401–500
Millennium: 1st millennium
1–1000
Years ago: 1,618
1618 years before 2026.

In other calendars

Hebrew: 4168 / 4169 AM
Rosh Hashanah falls in September/October.
Chinese: Year of the zodiac:Earth zodiac:Monkey
Sexagenary cycle position 45 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 951 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Ethiopian: 400 / 401 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 330 / 329 Saka
Indian national calendar; year starts in March.

Properties

Parity: Even
Digit count: 3
Digit sum: 12
Digit product: 0
Digital root: 3
Palindrome: No
Bit width: 9 bits
Reversed: 804
Recamán's sequence: a(500) = 408
Square (n²): 166,464
Cube (n³): 67,917,312
Divisor count: 16
σ(n) — sum of divisors: 1,080
φ(n) — Euler's totient: 128
Sum of prime factors: 26

Primality

Prime factorization: 2 ³ × 3 × 17

Nearest primes: 401 (−7) · 409 (+1)

Divisors & multiples

All divisors (16)

1 · 2 · 3 · 4 · 6 · 8 · 12 · 17 · 24 · 34 · 51 · 68 · 102 · 136 · 204 (half) · 408

Aliquot sum (sum of proper divisors): 672

Factor pairs (a × b = 408)

1 × 408

2 × 204

3 × 136

4 × 102

6 × 68

8 × 51

12 × 34

17 × 24

First multiples

408 · 816 (double) · 1,224 · 1,632 · 2,040 · 2,448 · 2,856 · 3,264 · 3,672 · 4,080

Sums & aliquot sequence

As consecutive integers: 135 + 136 + 137 18 + 19 + … + 33 16 + 17 + … + 32

Aliquot sequence: 408 → 672 → 1,344 → 2,720 → 4,084 → 3,070 → 2,474 → 1,240 → 1,640 → 2,140 → 2,396 → 1,804 → 1,724 → 1,300 → 1,738 → 1,142 → 574 — unresolved within range

Continued fraction of √n

√408 = [20; (5, 40)]

Period length 2 — the block in parentheses repeats forever.

Representations

In words: four hundred eight
Ordinal: 408th
Roman numeral: CDVIII
Binary: 110011000
Octal: 630
Hexadecimal: 0x198
Base64: AZg=
One's complement: 65,127 (16-bit)
Scientific notation: 4.08 × 10²
As a duration: 408 s = 6 minutes, 48 seconds

In other bases

ternary (3) 120010

quaternary (4) 12120

quinary (5) 3113

senary (6) 1520

septenary (7) 1122

nonary (9) 503

undecimal (11) 341

duodecimal (12) 2a0

tridecimal (13) 255

tetradecimal (14) 212

pentadecimal (15) 1c3

Palindromic in base 5, base 14

As an angle

408° = 1 × 360° + 48°

48° ≈ 0.838 rad

Compass bearing: NE (northeast)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓍢𓍢𓍢𓍢𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian): υηʹ
Mayan (base 20): 𝋡·𝋠·𝋨
Chinese: 四百零八
Chinese (financial): 肆佰零捌

In other modern scripts

Eastern Arabic ٤٠٨ Devanagari ४०८ Bengali ৪০৮ Tamil ௪௦௮ Thai ๔๐๘ Tibetan ༤༠༨ Khmer ៤០៨ Lao ໔໐໘ Burmese ၄၀၈

Digit at this position in famous constants

π — Pi (π): Digit 408 = 7
e — Euler's number (e): Digit 408 = 1
φ — Golden ratio (φ): Digit 408 = 5
√2 — Pythagoras's (√2): Digit 408 = 9
ln 2 — Natural log of 2: Digit 408 = 4
γ — Euler-Mascheroni (γ): Digit 408 = 7

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 408, here are decompositions:

7 + 401 = 408
11 + 397 = 408
19 + 389 = 408
29 + 379 = 408
41 + 367 = 408
59 + 349 = 408
61 + 347 = 408
71 + 337 = 408

Showing the first eight; more decompositions exist.

Unicode codepoint

Latin Capital Letter K With Hook

U+0198

Uppercase letter (Lu)

UTF-8 encoding: C6 98 (2 bytes).

Lookup U+0198 on Compart ↗ Lookup on FileFormat.Info ↗

HTTP status code

HTTP 408 Request Timeout — Server timed out waiting for the request.

4xx class: Client Error.

Hex color

#000198

RGB(0, 1, 152)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.1.152.

Address: 0.0.1.152
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.1.152

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

NANP area code 408

The number 408 is an active NANP area code (North American Numbering Plan).

Primary area: San Jose
Region: California
Country: United States

Most NANP area codes have multiple overlays in dense regions; the primary area listed is the historic/largest population center for this code.

Look up area code 408 ↗

Musical pitch

Heard as a frequency, 408 Hz is closest to:

Concert pitch (A4 = 440 Hz): G♯4 (415.3 Hz, -31¢)
Scientific pitch (C4 = 256 Hz): G♯4 (406.4 Hz, +7¢)
Baroque pitch (A4 = 415 Hz): A4 (415 Hz, -29¢)