Number

1,961

1,961 is a composite number, odd, a calendar year.

Arithmetic Number Deficient Number Flippable Odious Number Pernicious Number Recamán's Sequence Semiprime Squarefree Strobogrammatic Year

Notable events — 1961 AD

Jan 20 John F. Kennedy is inaugurated as the 35th US president.
Apr 12 Yuri Gagarin becomes the first human in space aboard Vostok 1.
Apr 17 The CIA-backed Bay of Pigs invasion of Cuba fails.
May 5 Alan Shepard becomes the first American in space.
Aug 13 East Germany begins building the Berlin Wall.

Events compiled from Wikipedia ↗ · Licensed CC BY-SA 4.0

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: Sunday
January 1, 1961
Ended on: Sunday
December 31, 1961
Friday the 13ths: 2
2 Friday the 13ths this year.
Easter Sunday: April 2
Sunday, April 2, 1961
Decade: 1960s
1960–1969
Century: 20th century
1901–2000
Millennium: 2nd millennium
1001–2000
Years ago: 65
65 years before 2026.

In other calendars

Hebrew: 5721 / 5722 AM
Rosh Hashanah falls in September/October.
Islamic Hijri: 1380 / 1381 AH
Lunar calendar; year spans differ from Gregorian.
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: 2504 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri: 1339 / 1340 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian: 1953 / 1954 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 1883 / 1882 Saka
Indian national calendar; year starts in March.
Japanese: Shōwa 36
Reign-era counting from the start of each emperor's reign.

Properties

Parity: Odd
Digit count: 4
Digit sum: 17
Digit product: 54
Digital root: 8
Palindrome: No
Bit width: 11 bits
Reversed: 1,691
Recamán's sequence: a(3,829) = 1,961
Square (n²): 3,845,521
Cube (n³): 7,541,066,681
Divisor count: 4
σ(n) — sum of divisors: 2,052
φ(n) — Euler's totient: 1,872
Sum of prime factors: 90

Primality

Prime factorization: 37 × 53

Nearest primes: 1,951 (−10) · 1,973 (+12)

Divisors & multiples

All divisors (4)

1 · 37 · 53 · 1961

Aliquot sum (sum of proper divisors): 91

Factor pairs (a × b = 1,961)

1 × 1961

37 × 53

First multiples

1,961 · 3,922 (double) · 5,883 · 7,844 · 9,805 · 11,766 · 13,727 · 15,688 · 17,649 · 19,610

Sums & aliquot sequence

As a sum of two squares: 5² + 44² = 19² + 40²

As consecutive integers: 980 + 981 35 + 36 + … + 71 11 + 12 + … + 63

Aliquot sequence: 1,961 → 91 → 21 → 11 → 1 → 0 — terminates at zero

Representations

In words: one thousand nine hundred sixty-one
Ordinal: 1961st
Roman numeral: MCMLXI
Binary: 11110101001
Octal: 3651
Hexadecimal: 0x7A9
Base64: B6k=
One's complement: 63,574 (16-bit)

In other bases

ternary (3) 2200122

quaternary (4) 132221

quinary (5) 30321

senary (6) 13025

septenary (7) 5501

nonary (9) 2618

undecimal (11) 1523

duodecimal (12) 1175

tridecimal (13) b7b

tetradecimal (14) a01

pentadecimal (15) 8ab

Historical numeral systems

Babylonian (base 60): 𒌋𒌋𒌋𒁹𒁹 𒌋𒌋𒌋𒌋𒁹
Egyptian hieroglyphic: 𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓏺
Greek (Milesian): ͵αϡξαʹ
Mayan (base 20): 𝋤·𝋲·𝋡
Chinese: 一千九百六十一
Chinese (financial): 壹仟玖佰陸拾壹

In other modern scripts

Eastern Arabic ١٩٦١ Devanagari १९६१ Bengali ১৯৬১ Tamil ௧௯௬௧ Thai ๑๙๖๑ Tibetan ༡༩༦༡ Khmer ១៩៦១ Lao ໑໙໖໑ Burmese ၁၉၆၁

Digit at this position in famous constants

π — Pi (π): Digit 1,961 = 5
e — Euler's number (e): Digit 1,961 = 7
φ — Golden ratio (φ): Digit 1,961 = 0
√2 — Pythagoras's (√2): Digit 1,961 = 5
ln 2 — Natural log of 2: Digit 1,961 = 7
γ — Euler-Mascheroni (γ): Digit 1,961 = 5

Also seen as

Unicode codepoint

Thaana Eebeefili

U+07A9

Non-spacing mark (Mn)

UTF-8 encoding: DE A9 (2 bytes).

Lookup U+07A9 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#0007A9

RGB(0, 7, 169)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.7.169.

Address: 0.0.7.169
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.7.169

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

Position in π

The digit sequence 1961 first appears in π at position 2,997 of the decimal expansion (the 2,997ordinal-suffix:th digit after the integer 3).

Search range: the first 1,000,000 fractional digits of π. Any 6-digit-or-shorter string is virtually guaranteed to appear in there — the more interesting signal is the position.

Look up 1961 on Pi Search ↗