12979
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 28
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 12980
- Proper Divisor Sum (Aliquot Sum)
- 1
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 12978
- Möbius Function
- -1
- Radical
- 12979
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- no
- Triangular Number
- no
- Perfect Square
- no
- Perfect Cube
- no
- Pentagonal Number
- no
- Hexagonal Number
- no
- Lucas Number
- no
- Tetrahedral Number
- no
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 50
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 1546
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 70 ones.at n=17A031838
- Primes whose sum of digits is the perfect number 28.at n=31A048517
- Discriminants of imaginary quadratic fields with class number 25 (negated).at n=25A056987
- Primes which are sandwiched between two numbers having the same unordered canonical form.at n=38A074460
- Row sums of triangular matrix A102098, which shifts upward to exclude the main diagonal under matrix cube.at n=4A102100
- G.f.: Sum((1-x)^(2*l)*Sum(x^((2*l-1)*k)/(1-2*x+x^k)^(2*l),k=1..infinity),l=1..infinity).at n=14A105205
- First differences of A000166.at n=7A105926
- Zsigmondy numbers for a = 5, b = 3: Zs(n, 5, 3) is the greatest divisor of 5^n - 3^n (A005058) that is relatively prime to 5^m - 3^m for all positive integers m < n.at n=17A109347
- Primes p such that the decimal expansion of p remains prime under two iterations of base-10 to base-2 conversions.at n=5A123266
- Primes congruent to 36 mod 43.at n=40A142285
- Primes congruent to 7 mod 47.at n=35A142358
- Primes congruent to 43 mod 49.at n=36A142450
- Primes congruent to 47 mod 53.at n=31A142577
- Primes congruent to 54 mod 55.at n=39A142640
- Primes congruent to 58 mod 59.at n=24A142785
- Primes congruent to 47 mod 61.at n=25A142845
- Primes which are anagrams of cubes.at n=29A161854
- Integers whose binary digits "1" define, if sorted into a quadrant shape whose right angle lies in a Go board corner, same colored Go stones that surely live all, but not if any stone is omitted.at n=21A166537
- Primes which are the sum of three distinct positive cubes in two or more distinct ways.at n=8A180088
- E.g.f. A(x) satisfies differential equation A'''(x)=A(x)+1/2*A(x)^2, A(0)=0, A'(0)=1, A''(0)=1, A'''(0)=1.at n=13A200542