1678
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 22
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 2520
- Proper Divisor Sum (Aliquot Sum)
- 842
- 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
- 838
- Möbius Function
- 1
- Radical
- 1678
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 86
- Smith Number
- yes
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- yes
- Odd
- no
Appears in sequences
- a(n) = solution to the postage stamp problem with 3 denominations and n stamps.at n=27A001208
- Convolution of A002024 with itself.at n=45A004797
- Numbers n such that n^32 + 1 is prime.at n=30A006315
- Coordination sequence T3 for Zeolite Code AEL.at n=27A008006
- Coordination sequence T2 for Zeolite Code AFO.at n=27A008016
- Coordination sequence T1 for Zeolite Code BOG.at n=29A008049
- Coordination sequence T2 for Zeolite Code EPI.at n=26A008091
- Coordination sequence T4 for Zeolite Code RUT.at n=27A009900
- Coordination sequence T2 for Zeolite Code SAO.at n=32A019572
- Coordination sequence T4 for Zeolite Code SAO.at n=32A019574
- Numbers k such that the continued fraction for sqrt(k) has period 32.at n=22A020371
- a(n) = Sum_{k >= 1} floor(2*tau^(n-k)).at n=12A020957
- Fibonacci sequence beginning 3, 17.at n=11A022127
- Numbers whose least quadratic nonresidue (A020649) is 11.at n=9A025024
- a(n) = (d(n)-r(n))/2, where d = A026057 and r is the periodic sequence with fundamental period (0,0,1,0).at n=20A026058
- a(n) = n^2 - 3.at n=39A028872
- [ exp(11/13)*n! ].at n=5A030923
- 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 40.at n=6A031538
- Digit sum of composite even number equals digit sum of juxtaposition of its prime factors (counted with multiplicity).at n=35A036924
- Even numbers k such that b(k) is greater than b(k-1) and b(k+1); b(k) = A033178(k).at n=20A038007