138,821
138,821 is a prime, odd.
138,821 (one hundred thirty-eight thousand eight hundred twenty-one) is an odd 6-digit number. It is a prime number — divisible only by 1 and itself. Written other ways, in hexadecimal, 0x21E45.
Interestingness
Properties
- Parity
- Odd
- Digit count
- 6
- Digit sum
- 23
- Digit product
- 384
- Digital root
- 5
- Palindrome
- No
- Bit width
- 18 bits
- Reversed
- 128,831
- Recamán's sequence
- a(491,185) = 138,821
- Square (n²)
- 19,271,270,041
- Cube (n³)
- 2,675,256,978,361,661
- Divisor count
- 2
- σ(n) — sum of divisors
- 138,822
- φ(n) — Euler's totient
- 138,820
Primality
138,821 is prime. It has exactly two divisors: 1 and itself.
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√138,821 = [372; (1, 1, 2, 2, 1, 1, 1, 8, 7, 2, 1, 43, 6, 1, 1, 2, 1, 148, 3, 6, 1, 1, 1, 2, …)]
Representations
- In words
- one hundred thirty-eight thousand eight hundred twenty-one
- Ordinal
- 138821st
- Binary
- 100001111001000101
- Octal
- 417105
- Hexadecimal
- 0x21E45
- Base64
- Ah5F
- One's complement
- 4,294,828,474 (32-bit)
- Scientific notation
- 1.38821 × 10⁵
- As a duration
- 138,821 s = 1 day, 14 hours, 33 minutes, 41 seconds
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒁹
- Egyptian hieroglyphic
- 𓆐𓂍𓂍𓂍𓆼𓆼𓆼𓆼𓆼𓆼𓆼𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓏺
- Greek (Milesian)
- ͵ρληωκαʹ
- Mayan (base 20)
- 𝋱·𝋧·𝋡·𝋡
- Chinese
- 一十三萬八千八百二十一
- Chinese (financial)
- 壹拾參萬捌仟捌佰貳拾壹
Also seen as
UTF-8 encoding: F0 A1 B9 85 (4 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.2.30.69.
- Address
- 0.2.30.69
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.2.30.69
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 138,821 and was likely granted around 1872.
Patent numbers below 100,000 are excluded as too ambiguous; modern numbering currently reaches roughly 12.5 million.
The digit sequence 138821 first appears in π at position 480,290 of the decimal expansion (the 480,290ordinal-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.
Related reading
- Prime numbers — The building blocks of arithmetic: what primes are, why they matter, and how we find them.
- Mayan numerals — Vigesimal dots-and-bars with a shell zero — one of the earliest true zeros.