8621
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
- 4
- Divisor Sum
- 8892
- Proper Divisor Sum (Aliquot Sum)
- 271
- 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
- 8352
- Möbius Function
- 1
- Radical
- 8621
- 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
- 171
- 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
- 5th-order maximal independent sets in cycle graph.at n=51A007388
- Expansion of g.f. 1/((1 - 3*x)*(1 - 4*x)*(1 - 7*x)).at n=4A016801
- Number of partitions of n into parts not of form 4k+2, 24k, 24k+3 or 24k-3. Also number of partitions in which no odd part is repeated, with 1 part of size less than or equal to 2 and where differences between parts at distance 5 are greater than 1 when the smallest part is odd and greater than 2 when the smallest part is even.at n=51A036030
- Number of digits in n-th term of A061482.at n=16A061902
- Semiprimes p1*p2 such that p2 > p1 and p2 mod p1 = 11.at n=28A064909
- Frobenius number of the numerical semigroup generated by three consecutive pentagonal numbers.at n=11A069757
- Iccanobirt numbers (11 of 15): a(n) = R(a(n-1) + R(a(n-2)) + R(a(n-3))), where R is the digit reversal function A004086.at n=17A102121
- Iccanobirt semiprimes (11 of 15): Semiprime numbers in A102121.at n=3A102201
- The (1,4) entry in the matrix M^n, where M is the 4 X 4 matrix [[0,-1,1,0],[0,0,-1,1],[1,1,1,0],[0,1,1,1]].at n=20A122822
- a(n) = 64*n^3 - 168*n^2 + 148*n - 43.at n=5A160250
- Positive numbers y such that y^2 is of the form x^2+(x+151)^2 with integer x.at n=8A161483
- Numbers which do not reach zero under either of the iterations: x -> floor(sqrt(x)) * (x - floor(sqrt(x))^2) or y -> ceiling(sqrt(y)) * (ceiling(sqrt(y))^2 - y).at n=8A219963
- (Product(primitive roots of p) - 1)/p, where p = prime(n) and n > 2.at n=5A222009
- Numerator of a(n) where a(0) = a(1) = a(2) = 1, a(n) * (a(n) + a(n+3)) = (a(n) + 2*a(n+2)) * (a(n) + a(n+2)).at n=5A237887
- a(n) = ceiling(Pi*n^3).at n=14A247194
- Product of n and the sum of remainders of n mod k, for k = 1, 2, 3, ..., n.at n=36A256532
- Partial sums of A304077.at n=38A304079
- Sum of the second largest parts in the partitions of n into 5 parts.at n=38A308826
- Consecutive terms that appear more than once in A014237.at n=39A322155
- Numbers of graphs which are double triangle descendants of K_5 with four more vertices than triangles.at n=25A332735