Number

390

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

Abundant Number Arithmetic Number Evil Number Gapful Number Practical Number Recamán's Sequence Semiperfect Number Squarefree Year

Historical context — 390 AD

Calendar year

Year 390 (CCCXC) was a common year starting on Tuesday of the Julian calendar.

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Historical context — 390 BC

Calendar year

Year 390 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: Monday
January 1, 390
Ended on: Monday
December 31, 390
Friday the 13ths: 2
2 Friday the 13ths this year.
Decade: 390s
390–399
Century: 4th century
301–400
Millennium: 1st millennium
1–1000
Years ago: 1,636
1636 years before 2026.

In other calendars

Hebrew: 4150 / 4151 AM
Rosh Hashanah falls in September/October.
Chinese: Year of the zodiac:Metal zodiac:Tiger
Sexagenary cycle position 27 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 933 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Ethiopian: 382 / 383 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 312 / 311 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: 93
Recamán's sequence: a(2,472) = 390
Square (n²): 152,100
Cube (n³): 59,319,000
Divisor count: 16
σ(n) — sum of divisors: 1,008
φ(n) — Euler's totient: 96
Sum of prime factors: 23

Primality

Prime factorization: 2 × 3 × 5 × 13

Nearest primes: 389 (−1) · 397 (+7)

Divisors & multiples

All divisors (16)

1 · 2 · 3 · 5 · 6 · 10 · 13 · 15 · 26 · 30 · 39 · 65 · 78 · 130 · 195 (half) · 390

Aliquot sum (sum of proper divisors): 618

Factor pairs (a × b = 390)

1 × 390

2 × 195

3 × 130

5 × 78

6 × 65

10 × 39

13 × 30

15 × 26

First multiples

390 · 780 (double) · 1,170 · 1,560 · 1,950 · 2,340 · 2,730 · 3,120 · 3,510 · 3,900

Sums & aliquot sequence

As consecutive integers: 129 + 130 + 131 96 + 97 + 98 + 99 76 + 77 + 78 + 79 + 80 27 + 28 + … + 38

Aliquot sequence: 390 → 618 → 630 → 1,242 → 1,638 → 2,730 → 5,334 → 6,954 → 7,926 → 7,938 → 12,753 → 7,267 → 785 → 163 → 1 → 0 — terminates at zero

Representations

In words: three hundred ninety
Ordinal: 390th
Roman numeral: CCCXC
Binary: 110000110
Octal: 606
Hexadecimal: 0x186
Base64: AYY=
One's complement: 65,145 (16-bit)

In other bases

ternary (3) 112110

quaternary (4) 12012

quinary (5) 3030

senary (6) 1450

septenary (7) 1065

nonary (9) 473

undecimal (11) 325

duodecimal (12) 286

tridecimal (13) 240

tetradecimal (14) 1dc

pentadecimal (15) 1b0

Historical numeral systems

Babylonian (base 60): 𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋
Egyptian hieroglyphic: 𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆
Greek (Milesian): τϟʹ
Mayan (base 20): 𝋳·𝋪
Chinese: 三百九十
Chinese (financial): 參佰玖拾

In other modern scripts

Eastern Arabic ٣٩٠ Devanagari ३९० Bengali ৩৯০ Tamil ௩௯௦ Thai ๓๙๐ Tibetan ༣༩༠ Khmer ៣៩០ Lao ໓໙໐ Burmese ၃၉၀

Digit at this position in famous constants

π — Pi (π): Digit 390 = 5
e — Euler's number (e): Digit 390 = 7
φ — Golden ratio (φ): Digit 390 = 1
√2 — Pythagoras's (√2): Digit 390 = 0
ln 2 — Natural log of 2: Digit 390 = 8
γ — Euler-Mascheroni (γ): Digit 390 = 5

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 390, here are decompositions:

7 + 383 = 390
11 + 379 = 390
17 + 373 = 390
23 + 367 = 390
31 + 359 = 390
37 + 353 = 390
41 + 349 = 390
43 + 347 = 390

Showing the first eight; more decompositions exist.

Unicode codepoint

Latin Capital Letter Open O

U+0186

Uppercase letter (Lu)

UTF-8 encoding: C6 86 (2 bytes).

Lookup U+0186 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#000186

RGB(0, 1, 134)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.1.134.

Address: 0.0.1.134
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.1.134

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