6631
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 7000
- Proper Divisor Sum (Aliquot Sum)
- 369
- 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
- 6264
- Möbius Function
- 1
- Radical
- 6631
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 137
- 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
- Expansion of 1/(1-x^5-x^6-x^7-x^8-x^9-x^10-x^11-x^12-x^13).at n=40A017844
- a(n) = 1*t(n) + 2*t(n-1) + ... + k*t(n+1-k), where k=floor((n+1)/2) and t = A008578 ({1} U primes).at n=27A023862
- a(n) = 1*prime(n) + 2*prime(n-1) + ... + k*prime(n+1-k), where k=floor((n+1)/2) and prime(n) is the n-th prime.at n=26A023870
- Numbers in which all pairs of consecutive base-8 digits differ by 3.at n=48A033079
- a(1) = 2; a(n) is smallest number >= a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.at n=43A033679
- Number of partitions satisfying cn(0,5) = cn(2,5) + cn(3,5).at n=44A039859
- Numbers whose base-7 representation contains exactly four 2's.at n=24A043404
- Shifts left under transform in formula line.at n=46A052336
- Second 11-gonal (or hendecagonal) numbers: a(n) = n*(9*n+7)/2.at n=38A062728
- Generalization of the Genocchi numbers given by the Gandhi polynomials A(n+1,r) = r^3 A(n, r + 1) - (r - 1)^3 A(n, r); A(1,r) = r^3 - (r-1)^3.at n=4A064624
- Semiprimes p1*p2 such that p2>p1 and p2 mod p1 = 7.at n=35A064905
- Triangle of Gandhi polynomial coefficients.at n=16A065747
- a(n+1) is the smallest number > a(n) such that the digits of a(n)^3 are all (with multiplicity) properly contained in the digits of a(n+1)^3, with a(0)=1.at n=6A067971
- a(n+1) is the smallest number > a(n) such that the digits of a(n)^3 are all (with multiplicity) contained in the digits of a(n+1)^3, with a(0)=1.at n=7A067973
- Positions of A080313 in A014486.at n=21A080312
- a(n) = n!*Sum_{k=0..n} (-1)^(n-k)*Stirling1(n,k)/k!.at n=5A119390
- Least positive number k such that 2^k mod k = 2n, or 0 if no such k exists.at n=45A122182
- a(n) = n_t(n) where t() = triangular numbers A000217.at n=50A122627
- T(n,k) is the number of unlabeled acyclic single-source automata with n transient states on a (k+1)-letter input alphabet.at n=18A128249
- Numbers n such that phi(phi(n)) + sigma(sigma(n)) is a 4th power.at n=13A172464