The term "43 (number)" is not an established concept in encyclopedic sources as a unique subject requiring dedicated coverage beyond general mathematical knowledge.
Definition:
"43" is a natural number following 42 and preceding 44. It is represented in the decimal system by the digits "4" and "3". As a cardinal number, it denotes a quantity of forty-three; as an ordinal number, it corresponds to "forty-third".
Overview:
In mathematics, 43 is an integer and a prime number, meaning it has no positive divisors other than 1 and itself. It is the 13th smallest prime number. It appears in various arithmetic and number-theoretic contexts, such as sequences and equations, but does not hold a uniquely prominent status in mathematical theory compared to numbers like pi, e, or larger named primes.
Etymology/Origin:
The term "43" originates from the Indo-Arabic numeral system, which is the standard system for denoting integers worldwide. The name "forty-three" comes from the combination of "forty" (from Old English fēowertig, meaning four tens) and "three", reflecting its base-10 composition (4×10 + 3). The numeral symbol "43" has evolved from earlier Hindu-Arabic scripts through medieval European adoption.
Characteristics:
- 43 is an odd number.
- It is a prime number (divisible only by 1 and 43).
- It is a Heegner number, meaning it satisfies certain conditions in complex multiplication and number theory; specifically, it is one of the nine Heegner numbers (−1, −2, −3, −7, −11, −19, −43, −67, −163) linked to imaginary quadratic fields with class number 1.
- 43 is a lucky number in the context of the "lucky number" sieve, a process similar to the Sieve of Eratosthenes.
- It cannot be expressed as the sum of any integer and its digits (making it a Harshad number rejector); hence, 43 is a "self number" or "Devaraj number".
- In science, 43 is the atomic number of technetium (Tc), the first element in the periodic table to be artificially produced.
Related Topics:
- Prime numbers
- Number theory
- Heegner numbers
- Lucky numbers
- Decimal numeral system
- Technetium (chemistry)
- Natural numbers
Note: While 43 has identifiable mathematical properties, the standalone term "43 (number)" does not constitute a distinct encyclopedic topic beyond these general numerical attributes. No specialized cultural, historical, or scientific phenomenon is uniquely and widely recognized under the label "43 (number)" that would warrant standalone encyclopedic treatment beyond the general discussion of the number 43.