1893
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 2528
- Proper Divisor Sum (Aliquot Sum)
- 635
- 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
- 1260
- Möbius Function
- 1
- Radical
- 1893
- 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
- 37
- Smith Number
- no
- 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
- no
- Odd
- yes
Appears in sequences
- a(n) = least m such that if a/b < c/d where a,b,c,d are integers in [0,n], then a/b < k/m < c/d for some integer k.at n=49A001000
- Number of sublattices of index n in generic 3-dimensional lattice.at n=42A001001
- Central polygonal numbers: a(n) = n^2 - n + 1.at n=44A002061
- Numbers k such that k, k+1 and k+2 have the same number of divisors.at n=34A005238
- a(n) = a(n-1) + a(n - 1 - number of even terms so far).at n=29A006336
- Coordination sequence T1 for Zeolite Code AWW.at n=31A008045
- Coordination sequence T1 for Zeolite Code MFS.at n=27A008173
- Coordination sequence T2 for Zeolite Code RTH.at n=30A009894
- Coordination sequence T3 for Zeolite Code RTH.at n=30A009895
- Coordination sequence T5 for Zeolite Code VNI.at n=27A009911
- Expansion of 1/(1-x^9-x^10-x^11-x^12-x^13-x^14-x^15-x^16-x^17-x^18-x^19).at n=55A017886
- Define the generalized Pisot sequence T(a(0),a(1)) by: a(n+2) is the greatest integer such that a(n+2)/a(n+1) < a(n+1)/a(n). This is T(3,5).at n=20A018917
- Index of 5^n within sequence of numbers of form 3^i*5^j.at n=50A022338
- Numbers k such that Fibonacci(k) == 2 (mod k).at n=33A023174
- Convolution of odd numbers and A000201.at n=14A023658
- a(n) = Sum_{k = 1..n} T(k,k-1), where T is the array defined in A024996.at n=8A026079
- Sequence satisfies T^2(a)=a, where T is defined below.at n=44A027586
- Golc sequence in base 2. Left to right concatenation of n,int(log_2(n)),int(log_2(int(log_2(n)))),... in base 2.at n=28A028432
- 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 28.at n=19A031526
- Lucky numbers with size of gaps equal to 14 (upper terms).at n=8A031897