8159
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 23
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 8400
- Proper Divisor Sum (Aliquot Sum)
- 241
- 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
- 7920
- Möbius Function
- 1
- Radical
- 8159
- 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
- 65
- 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
- a(n) = round(n*phi^11), where phi is the golden ratio, A001622.at n=41A004946
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 89.at n=22A031587
- Sums of 12 distinct powers of 2.at n=7A038463
- Triangle in A059032 read by rows from left to right.at n=29A059033
- Triangle in A059032 read by rows in natural order.at n=29A059034
- Nonprime numbers n such that q=phi(n)/(sigma(n)-n-1) is an integer and n is not a prime square.at n=43A070161
- a(1)=1; a(n) = a(n-1) + [sum of all decimal digits present so far in the sequence].at n=38A072921
- Number of conjugacy classes in the symmetric group S_n with distinct cardinality.at n=37A073906
- Group the composite numbers so that the sum of the n-th group is a multiple of the n-th prime: (4), (6), (8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22), (24, 25), (26, 27, 28, 30, 32), (33, 34, ...), ... Sequence gives sum of n-th group.at n=12A074124
- Least nontrivial multiple of the n-th prime beginning with 8.at n=45A078292
- Inverse permutation to sequence A101319 (assuming A101319 is a permutation).at n=52A100805
- Numbers k which divide the sum of the Fibonacci numbers F(1) through F(k) and such that k is not a multiple of 24.at n=10A124456
- a(n) = prime(2*n^2) - 2*n^2.at n=23A141086
- Composite terms in A143578.at n=42A142591
- a(n) = the smallest positive integer m with exactly n (no more, no fewer) distinct primes represented in binary as substrings within the binary representation of m.at n=23A146526
- Monotonic ordering of set S generated by these rules: if x and y are in S then 5xy-x-y is in S, and 1 is in S.at n=28A192528
- Number of 2 X 2 matrices with all elements in {0,1,...,n} and determinant in {-1,0,1}.at n=28A209993
- Greatest number (in decimal representation) with n nonprime substrings in binary representation (substrings with leading zeros are considered to be nonprime).at n=48A217112
- Minimal natural number (in decimal representation) with n prime substrings in binary representation (substrings with leading zeros are considered to be nonprime).at n=42A217302
- a(n) = Sum_{i=0..n} digsum_4(i)^4, where digsum_4(i) = A053737(i).at n=29A231667