6171
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 9576
- Proper Divisor Sum (Aliquot Sum)
- 3405
- 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
- 3520
- Möbius Function
- 0
- Radical
- 561
- 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
- 261
- Smith Number
- yes
- 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
- In the '3x+1' problem, these values for the starting value set new records for number of steps to reach 1.at n=25A006877
- a(n) = floor(n*(n-1)*(n-2)/30).at n=58A011912
- Positive integers n such that 2^n == 2^11 (mod n).at n=61A015935
- 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 77.at n=18A031575
- In the '3x+1' problem, these values for the starting value set new records for number of steps to reach 1.at n=19A033958
- Numbers whose base-5 representation contains exactly three 1's and three 4's.at n=8A045262
- Numbers m such that there are precisely 3 groups of order m.at n=30A055561
- At stage 1, start with a unit square. At each successive stage add 4*(n-1) new squares around outside with edge-to-edge contacts. Sequence gives number of squares (regardless of size) at n-th stage.at n=20A056640
- Numbers k such that the product of the digits of k is equal to the sum of the prime factors of k, counted with multiplicity.at n=22A065774
- Numbers k such that phi(k) mod core(k) = 1 where core(k) is the squarefree part of k.at n=41A069946
- n sets a record for the number of primes in {n, f(n), f(f(n)), ..., 1}, where f is the Collatz function defined by f(x) = x/2 if x is even; f(x) = 3x + 1 if x is odd.at n=12A078373
- a(n+1) = a(n)+greatest prime divisor of a(n-1).at n=41A078695
- Column 5 of triangle A091602.at n=37A091608
- Frequency of the hexadecimal 4 in the first 10^n hexadecimal digits of Pi.at n=4A099337
- Concatenations of pairs of primes that differ by 10.at n=7A104719
- Numbers n such that pi(n)=pi(d_1!)+pi(d_2!)+...+pi(d_k!) where d_1 d_2 ...d_k is the decimal expansion of n.at n=10A105327
- Numbers n such that (n + prime(n)), (n+1 + prime(n+1)) and (n+2 + prime(n+2)) are divisible by 5.at n=39A107581
- a(1) = 7, a(n) = least k such that concatenation of n copies of k with all previous concatenation gives a prime.at n=36A111475
- Dropping first and last digit of n leaves its largest prime factor.at n=29A114565
- Multiples of 17 containing a 17 in their decimal representation.at n=13A121037