5181
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 7584
- Proper Divisor Sum (Aliquot Sum)
- 2403
- 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
- 3120
- Möbius Function
- -1
- Radical
- 5181
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 41
- 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
- G.f.: 1/((1-x)*(1-x^2)*(1-x^3)^2*(1-x^4)*(1-x^5)).at n=38A003402
- Number of partitions of n into partition numbers.at n=49A007279
- Pseudoprimes to base 28.at n=26A020156
- Number of 2's in all partitions of n.at n=26A024786
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 46.at n=36A031544
- Numbers k such that 231*2^k+1 is prime.at n=43A032492
- Sort then Add, a(1)=15.at n=12A033898
- Sort then Add, a(1)=21.at n=11A033901
- G.f.: ( 1 - x^2 - sqrt( 1 - 2*x^2 - 4*x^3 - 3*x^4 ) ) / ( 2*x^3 ).at n=16A050253
- Numbers k such that 2*3^k + 7 is prime.at n=16A059326
- Number of primes between n^5 and (n+1)^5.at n=10A062517
- Third row of number array A082105.at n=35A082109
- q such that p^4 + q^4 = r^4 + s^4 = a(n).at n=23A088665
- Numbers k such that 5*k! - 1 is prime.at n=17A099351
- Number of partitions of the n-th minimal number into distinct minimal numbers.at n=27A099388
- Structured octagonal anti-diamond numbers (vertex structure 7).at n=10A100187
- Numbers k such that tau(k) = tau(k+1) mod 691, where tau is Ramanujan's tau function A000594.at n=5A121733
- Twin prime products minus 2.at n=7A124659
- Product of successive primes minus 2.at n=19A124669
- Triangle T(n,k) = 4*binomial(n,k)^2 - 3, read by rows, 0<=k<=n.at n=47A141596