70
70 is a composite number, even, a calendar year.
70 (seventy) is an even 2-digit number. It is a composite number with 8 divisors, and factors as 2 × 5 × 7. Its proper divisors sum to 74, more than the number itself, making it an abundant number. Written other ways, in Roman numerals it is LXX and in binary, 1000110.
Interestingness
Notable events — 70 AD
- Sep 8 Roman forces under Titus sack Jerusalem and destroy the Second Temple.
Events compiled from Wikipedia ↗ · Licensed CC BY-SA 4.0
Historical context — 70 BC
Calendar year
Year 70 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
-
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
-
Wednesday
January 1, 70
- Ended on
-
Wednesday
December 31, 70
- Friday the 13ths
-
1
One Friday the 13th this year.
- Decade
-
70s
70–79
- Century
-
1st century
1–100
- Millennium
-
1st millennium
1–1000
- Years ago
-
1,956
1956 years before 2026.
In other calendars
- Hebrew
-
3830 / 3831 AM
Rosh Hashanah falls in September/October.
- Chinese
-
Year of the zodiac:Metal zodiac:Horse
Sexagenary cycle position 7 of 60. Lunar new year falls in late January / mid-February.
- Buddhist Era
-
613 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Ethiopian
-
62 / 63 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
-8 / -9 Saka
Indian national calendar; year starts in March.
Cultural significance
Jesus sent out seventy disciples; the seventy nations of the world in Jewish tradition.
Luke 10:1; Genesis 10.
Sourced from Wikipedia (Numerology, Chinese numerology, Gematria, and per-culture articles).
Properties
Primality
Prime factorization: 2 × 5 × 7
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√70 = [8; (2, 1, 2, 1, 2, 16)]
Period length 6 — the block in parentheses repeats forever.
Representations
- In words
- seventy
- Ordinal
- 70th
- Roman numeral
- LXX
- Binary
- 1000110
- Octal
- 106
- Hexadecimal
- 0x46
- Base64
- Rg==
- One's complement
- 185 (8-bit)
- Scientific notation
- 7 × 10¹
- As a duration
- 70 s = 1 minute, 10 seconds
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒁹 𒌋
- Egyptian hieroglyphic
- 𓎆𓎆𓎆𓎆𓎆𓎆𓎆
- Greek (Milesian)
- οʹ
- Mayan (base 20)
- 𝋣·𝋪
- Chinese
- 七十
- Chinese (financial)
- 柒拾
Digit at this position in famous constants
- π — Pi (π)
- Digit 70 = 6
- e — Euler's number (e)
- Digit 70 = 6
- φ — Golden ratio (φ)
- Digit 70 = 0
- √2 — Pythagoras's (√2)
- Digit 70 = 2
- ln 2 — Natural log of 2
- Digit 70 = 3
- γ — Euler-Mascheroni (γ)
- Digit 70 = 7
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 70, here are decompositions:
- 3 + 67 = 70
- 11 + 59 = 70
- 17 + 53 = 70
- 23 + 47 = 70
- 29 + 41 = 70
As an ASCII codepoint, 70 is F. Printable ASCII character F.
As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.70.
- Address
- 0.0.0.70
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.0.70
Unspecified address (0.0.0.0/8) — "this network" placeholder.
Matches numbered highway designation:
- I-70 — Cove Fort, UT to Baltimore, MD.
Heard as a frequency, 70 Hz is closest to:
- Concert pitch (A4 = 440 Hz): C♯2 (69.3 Hz, +18¢)
- Scientific pitch (C4 = 256 Hz): D2 (71.8 Hz, -45¢ — about midway to C♯2)
- Baroque pitch (A4 = 415 Hz): D2 (69.2 Hz, +19¢)
As a MIDI note number, 70 is A♯4 (466.2 Hz at concert pitch).
On the periodic table, atomic number 70 is Ytterbium (Yb) — period 6.
Related reading
- Egyptian hieroglyphic numerals — Seven hieroglyphs for every power of ten, from a single stroke to a million.