138,720
138,720 is a composite number, even.
138,720 (one hundred thirty-eight thousand seven hundred twenty) is an even 6-digit number. It is a composite number with 72 divisors, and factors as 2⁵ × 3 × 5 × 17². Its proper divisors sum to 325,464, more than the number itself, making it an abundant number. Written other ways, in hexadecimal, 0x21DE0.
Interestingness
Properties
- Parity
- Even
- Digit count
- 6
- Digit sum
- 21
- Digit product
- 0
- Digital root
- 3
- Palindrome
- No
- Bit width
- 18 bits
- Reversed
- 27,831
- Recamán's sequence
- a(491,387) = 138,720
- Square (n²)
- 19,243,238,400
- Cube (n³)
- 2,669,422,030,848,000
- Divisor count
- 72
- σ(n) — sum of divisors
- 464,184
- φ(n) — Euler's totient
- 34,816
- Sum of prime factors
- 52
Primality
Prime factorization: 2 5 × 3 × 5 × 17 2
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√138,720 = [372; (2, 4, 1, 1, 1, 3, 6, 2, 3, 2, 3, 2, 6, 3, 1, 1, 1, 4, 2, 744)]
Period length 20 — the block in parentheses repeats forever.
Representations
- In words
- one hundred thirty-eight thousand seven hundred twenty
- Ordinal
- 138720th
- Binary
- 100001110111100000
- Octal
- 416740
- Hexadecimal
- 0x21DE0
- Base64
- Ah3g
- One's complement
- 4,294,828,575 (32-bit)
- Scientific notation
- 1.3872 × 10⁵
- As a duration
- 138,720 s = 1 day, 14 hours, 32 minutes
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒁹𒁹 ·
- Egyptian hieroglyphic
- 𓆐𓂍𓂍𓂍𓆼𓆼𓆼𓆼𓆼𓆼𓆼𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆
- Greek (Milesian)
- ͵ρληψκʹ
- Mayan (base 20)
- 𝋱·𝋦·𝋰·𝋠
- Chinese
- 一十三萬八千七百二十
- Chinese (financial)
- 壹拾參萬捌仟柒佰貳拾
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 138720, here are decompositions:
- 37 + 138683 = 138720
- 41 + 138679 = 138720
- 59 + 138661 = 138720
- 73 + 138647 = 138720
- 79 + 138641 = 138720
- 83 + 138637 = 138720
- 103 + 138617 = 138720
- 139 + 138581 = 138720
Showing the first eight; more decompositions exist.
UTF-8 encoding: F0 A1 B7 A0 (4 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.2.29.224.
- Address
- 0.2.29.224
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.2.29.224
Unspecified address (0.0.0.0/8) — "this network" placeholder.
This number falls in the range of US utility patent numbers. If it's a patent, it would be issued as US 138,720 and was likely granted around 1872.
Patent numbers below 100,000 are excluded as too ambiguous; modern numbering currently reaches roughly 12.5 million.
Related reading
- Babylonian numerals — The base-60 cuneiform system that gave us 60 minutes, 60 seconds, and 360°.