1279
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 1280
- Proper Divisor Sum (Aliquot Sum)
- 1
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 1278
- Möbius Function
- -1
- Radical
- 1279
- 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
- 132
- 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
- yes
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 207
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Mersenne exponents: primes p such that 2^p - 1 is prime. Then 2^p - 1 is called a Mersenne prime.at n=14A000043
- Number of bipartite partitions of n white objects and 4 black ones.at n=9A000465
- Degrees of primitive irreducible trinomials: n such that 2^n - 1 is a Mersenne prime and x^n + x^k + 1 is a primitive irreducible polynomial over GF(2) for some k with 0 < k < n.at n=10A001153
- Number of bipartite partitions of n white objects and 9 black ones.at n=4A002758
- a(n) = 1000*log_10(n) rounded to the nearest integer.at n=18A004226
- a(n) = ceiling(1000*log_10(n)).at n=18A004227
- Primes p such that 2p-1 is also prime.at n=39A005382
- Greater of twin primes.at n=42A006512
- a(n) = (n+3)*2^n - 1.at n=8A006589
- Primes of the form 2*k^2 + 29.at n=25A007641
- Noncubes such that some permutation of digits is a cube.at n=41A007940
- Coordination sequence T3 for Zeolite Code MFS.at n=22A008175
- Coordination sequence T2 for Zeolite Code AFX.at n=27A009865
- a(n) = 2*a(n-2) + 1.at n=16A010737
- Expansion of 1/(1-x^2-x^3-x^4-x^5-x^6-x^7).at n=18A013984
- From table of maximal epacts e(p) and corresponding primes p, for x_0=2, x_{m+1} = (x_m)^2-1; sequence gives p.at n=20A014426
- Numbers k such that sigma(k) + 4 = sigma(k+4).at n=45A015913
- Numbers k such that the continued fraction for sqrt(k) has period 60.at n=2A020399
- Pisot sequences E(5,7), P(5,7).at n=15A020711
- Pisot sequences E(7,10), P(7,10).at n=14A020721