15771
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 24064
- Proper Divisor Sum (Aliquot Sum)
- 8293
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 9000
- Möbius Function
- -1
- Radical
- 15771
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 3
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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 84
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- no
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- a(n) = a(n-1) + a(n-7), with a(i) = 1 for i = 0..6.at n=46A005709
- Expansion of 1/(1 - x^7 - x^8 - ...).at n=53A017901
- Multiplicity of highest weight (or singular) vectors associated with character chi_91 of Monster module.at n=44A034479
- Numbers whose base-5 representation contains exactly three 0's and three 1's.at n=24A045172
- Values of m, the main key or generating number for Pythagorean triangles in which S (the odd short leg) and U (the hypotenuse) are twin primes.at n=37A051891
- Self-convolution square-root of A118191, where A118191 is column 0 of the matrix square of triangle A118190 with A118190(n,k) = (5^k)^(n-k).at n=5A118195
- Triangle T, read by rows, that satisfies matrix equation: T + (T-I)^2 = C, where C is Pascal's triangle.at n=30A120903
- Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 1000-1100-0111-0100 pattern in any orientation.at n=10A147161
- Numbers n such that (n^6 + 1091)/4 is prime.at n=9A181112
- Number of partitions of n for which (number of occurrences of the least part) = (number of occurrences of greatest part).at n=44A236543
- Number of compositions (ordered partitions) of n into decimal palindromic primes (A002385).at n=28A286970
- Number of n X 4 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 3 or 6 neighboring 1s.at n=21A296550
- Number of pairs (lambda,mu) of partitions lambda of n and mu of seven with mu <= lambda (by diagram containment).at n=16A303857
- Sum of the squarefree parts of the partitions of n into 4 parts.at n=43A309479
- Expansion of Product_{k>=1} 1/((1 - x^k) * (1 - x^(2*k)) * (1 - x^(3*k))).at n=23A327042
- Number of partitions p of n such that (1/5)*max(p) is a part of p.at n=47A363068
- Number of compositions of 7*n-3 into parts 1 and 7.at n=6A373929