7641
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 11360
- Proper Divisor Sum (Aliquot Sum)
- 3719
- 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
- 5076
- Möbius Function
- 0
- Radical
- 849
- Omega Function (Ω)
- 4
- 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
- 31
- 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
- no
- Odd
- yes
Appears in sequences
- a(n) = n*(21*n-1)/2.at n=27A022278
- Arrange digits of squares in descending order.at n=42A028908
- Take list of squares, move left digit of each term to end of previous term.at n=43A032760
- Number of binary [ n,4 ] codes.at n=13A034358
- n has distinct digits in descending order and n=a+b where a has the digits of n in another order and b has the digits of n in ascending order (perhaps with leading zeros).at n=1A055158
- n has digits in descending order and n=a+b where a has the digits of n in another order and b has the digits of n in ascending order (perhaps with leading zeros).at n=1A055161
- Numbers k such that 5^k - 4 is prime.at n=8A059613
- a(n) = A077700(n+1)/A077700(n).at n=10A077701
- Numbers k such that both k and the k-th prime have nonincreasing digits.at n=46A116067
- Numbers k such that if you subtract k-reversed from k you get a natural number with the same digits as k.at n=5A121969
- G.f.: (1-2*x+2*x^2-x^3+x^4-x^5+2*x^6-2*x^7+x^8)/((1-x)^2*(1-x^2)*(1-x^3)*(1-x^6)).at n=48A127825
- Smallest number that can be written in exactly n ways as a sum of distinct repdigits of its decimal digits.at n=15A131367
- Sum of proper divisors of the number of partitions of n.at n=32A139055
- Triangle read by rows: n-th row is the expansion of the polynomial (x-F1)*(x-F2)*(x-F3)*...*(x-Fn).at n=32A158472
- a(n) = numerator of (Zeta(0,2,1/3) - Zeta(0,2,n+1/3)), where Zeta is the Hurwitz Zeta function.at n=3A173982
- Positive integers of the form (2*m^2+1)/11.at n=37A179088
- Number of lunar divisors (A087029) of the decimal numbers 1, 10, 11, 100, 101, 110, 111, 1000, ... .at n=14A186508
- Number of -n..n circular arrays x(0..4) of 5 elements with zero sums of x(i) and x(i)*x((i+1) mod 5).at n=39A202007
- Numbers a = b + c where a, b, and c contain the same decimal digits.at n=12A203024
- Number of ordered triples (w,x,y) with all terms in {1,...,n} and w^2>=x^2+y^2.at n=31A211636