6850
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 12834
- Proper Divisor Sum (Aliquot Sum)
- 5984
- 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
- 2720
- Möbius Function
- 0
- Radical
- 1370
- 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
- 57
- 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
- yes
- Odd
- no
Appears in sequences
- Maxima of the rows of the triangle A259095.at n=39A005577
- Expansion of e.g.f.: log(1+sin(log(1+x))).at n=7A009326
- Expansion of 1/Product_{m>=1} (1 - m*q^m)^30.at n=3A022754
- a(n) = (d(n)-r(n))/2, where d = A026057 and r is the periodic sequence with fundamental period (0,0,1,0).at n=36A026058
- a(n) = Sum_{k=0..n-2} T(n,k) * T(n,k+3), with T given by A026120.at n=3A027325
- Number of primes < n^3.at n=40A038098
- Numbers whose base-5 representation contains exactly three 0's and two 4's.at n=19A045216
- Numbers n such that n through n+5 have the same number of distinct prime factors.at n=11A045934
- a(n) = Sum_{i=0..floor(n/2)} T(2i,n-2i), array T as in A049747.at n=34A049750
- a(n) is the first number in the first run of at least n successive numbers, all having exactly 3 distinct prime factors.at n=5A080569
- Starting positions of strings of three 8's in the decimal expansion of Pi.at n=5A083637
- Number of primes < prime(n)^3.at n=12A086688
- Table read by rows: T(n,k)= z (z') or product of z with its complex conjugate, with z=Sum[binomial[n,t] I^t, {t,0,k}].at n=48A092821
- Minimal values of m=a^2+b^2=c^2+d^2 for each x=a+b+c+d=6*p (p=any odd prime).at n=10A093194
- Bisection of A001157: sigma_2(2n).at n=36A099979
- Maximal number of 1432 patterns in a permutation of 1,2,...,n.at n=25A100354
- a(n) = n*(20 + 15*n + n^2)/6.at n=29A101853
- Group the triangular numbers so that the n-th group sum is a multiple of n. 1, (3, 6, 10, 15), (21), (28), (36, 45, 55, 66, 78), (91, 105, 120, 136, 153, 171, 190), ... Sequence contains n-th group sum divided by n.at n=21A114032
- Triangle read by rows: T(n,k) is number of Dyck paths of semilength n having k ascents of length 3 (0<=k<=floor(n/3)). Also number of ordered trees with n edges that have k vertices of outdegree 3.at n=23A114506
- Triangle read by rows: T(n,k) is the number of permutations of {1,2,...,n} in which the last entry of the first increasing run is equal to k (1 <= k <= n).at n=33A134433