43 (number) facts for kids
This article is about the number 43. For the year, see 43.
Forty-three is a special number that comes right after forty-two and just before forty-four. It's an odd number, meaning you can't divide it evenly by two.
Forty-three is also known as a prime number. A prime number is a whole number greater than 1 that has only two factors (divisors): 1 and itself. This means you can only multiply 1 by 43 to get 43. It's the 14th prime number in the list, following numbers like 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, and 41.
Contents
What Makes 43 Special?
Numbers often have interesting properties beyond just being odd or prime. Forty-three is a unique number in many ways.
Mathematical Facts About 43
- Prime Number: As we learned, 43 is a prime number. This is one of its most important features.
- Centered Heptagonal Number: In geometry, a centered heptagonal number is a type of polygonal number that represents a heptagon (a seven-sided shape) with a dot in the middle and other dots arranged around it in layers. Forty-three is the third centered heptagonal number.
- Happy Number: A happy number is a number that eventually reaches 1 when replaced by the sum of the square of its digits. For example, for 43:
- 4² + 3² = 16 + 9 = 25
- 2² + 5² = 4 + 25 = 29
- 2² + 9² = 4 + 81 = 85
- 8² + 5² = 64 + 25 = 89
- 8² + 9² = 64 + 81 = 145
- 1² + 4² + 5² = 1 + 16 + 25 = 42
- 4² + 2² = 16 + 4 = 20
- 2² + 0² = 4
- 4² = 16
- 1² + 6² = 1 + 36 = 37
- 3² + 7² = 9 + 49 = 58
- 5² + 8² = 25 + 64 = 89 (we've seen this before, so it's a loop and not a happy number!)
- Safe Prime: A safe prime is a prime number of the form 2p + 1, where p is also a prime number. For 43, if p = 21, then 2(21) + 1 = 43. However, 21 is not a prime number, so 43 is not a safe prime.
How 43 Appears in Science
- Atomic Number: In chemistry, 43 is the atomic number of the element Technetium. Technetium is the lightest element that has no stable (non-radioactive) isotope. This means all forms of technetium are radioactive.
43 in Everyday Life
- Sports: In some sports, the number 43 might be a jersey number or a score.
- Age: Forty-three is an age that many people reach.
See also
Images for kids
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A friendly robot to help us learn about numbers!
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43 (number) Facts for Kids. Kiddle Encyclopedia.