1822
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 2736
- Proper Divisor Sum (Aliquot Sum)
- 914
- 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
- 910
- Möbius Function
- 1
- Radical
- 1822
- 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
- 42
- 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
- Coordination sequence T1 for Zeolite Code ERI and OFF.at n=31A008093
- Coordination sequence T4 for Zeolite Code GOO.at n=29A008114
- Coordination sequence T2 for Zeolite Code HEU.at n=28A008117
- Molien series for Weyl group E_8.at n=52A008582
- Molien series for A_5.at n=37A008628
- Year of birth of n-th President of U.S.A.at n=18A008745
- Year of birth of n-th President of U.S.A.at n=17A008745
- If a, b are in the sequence, so is ab+3.at n=43A009302
- Coordination sequence T2 for Zeolite Code RUT.at n=28A009898
- Expansion of e.g.f. log(cosh(x)-log(x+1)).at n=7A013497
- First occurrence of exactly n identical terms in A007448.at n=30A016046
- Coordination sequence T3 for Zeolite Code OSI.at n=28A016432
- Numbers k such that the continued fraction for sqrt(k) has period 48.at n=8A020387
- Expansion of 1/((1-x)(1-3x)(1-6x)(1-7x)).at n=3A021494
- Fibonacci sequence beginning 4, 18.at n=11A022384
- Numbers with exactly 6 1's in their ternary expansion.at n=13A023697
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = (odd natural numbers), t = (primes).at n=14A024603
- Numbers whose least quadratic nonresidue (A020649) is 7.at n=27A025023
- [ Sum{(log(j)-log(i))^2} ], 2 <= i < j <= n.at n=52A025206
- a(n) = a(1)*a(n-1) + a(2)*a(n-2) + ...+ a(n-1)*a(1) for n >= 5, with initial values 1,0,1,0.at n=14A025275