1628
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 3192
- Proper Divisor Sum (Aliquot Sum)
- 1564
- 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
- 720
- Möbius Function
- 0
- Radical
- 814
- Omega Function (Ω)
- 4
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 42
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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) = (9*n+1)*(9*n+8).at n=4A001534
- a(1) = 1; for n>1, a(n) = a(n-1) + 1 + sum of distinct prime factors of a(n-1) that are < a(n-1).at n=49A003508
- Sequence and first differences (A030124) together list all positive numbers exactly once.at n=51A005228
- Bishops on a 2n+1 X 2n+1 board (see Robinson paper for details).at n=5A005632
- Number of balanced ordered trees with n nodes.at n=15A007059
- Coordination sequence T1 for Zeolite Code BIK.at n=24A008047
- Coordination sequence T7 for Zeolite Code EUO.at n=25A008102
- Coordination sequence T9 for Zeolite Code EUO.at n=25A008104
- Coordination sequence T7 for Zeolite Code MEL.at n=26A008156
- Coordination sequence T8 for Zeolite Code MFS.at n=25A008180
- Expansion of g.f.: x^4/((1-x)*(1-x^2)^2*(1-x^3)).at n=49A008763
- If a, b in sequence, so is ab+4.at n=32A009303
- Coordination sequence T1 for Zeolite Code -WEN.at n=29A009862
- Numbers n such that phi(n) * sigma(n) + 16 is a perfect square.at n=36A015729
- Squares on infinite chessboard at n moves from center using a {2,3} fairy knight.at n=25A018839
- Number of monomials in expansion of determinant of an n X n Toeplitz matrix [ t(|i-j|) ] in terms of its entries.at n=8A019447
- a(n) = n*(27*n - 1)/2.at n=11A022284
- Number of 3's in n-th term of A022470.at n=31A022474
- Convolution of odd numbers and A001950.at n=11A023659
- a(n) is the sum of squares of the first n positive integers congruent to 2 mod 3.at n=7A024394