6219
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 8996
- Proper Divisor Sum (Aliquot Sum)
- 2777
- 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
- 4140
- Möbius Function
- 0
- Radical
- 2073
- Omega Function (Ω)
- 3
- 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
- 124
- 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
- no
- Odd
- yes
Appears in sequences
- Number of partitions of n into nonprime parts.at n=54A002095
- Coefficients of modular function G_4(tau).at n=28A005762
- 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=23A031575
- Numbers having four 4's in base 6.at n=19A043388
- Numbers whose base-5 representation contains exactly two 3's and three 4's.at n=17A045303
- a(n) = Sum_{k=0..n} S(k)*S(n-k), convolution of S=A001644 with itself.at n=10A073782
- Interprimes which are of the form s*prime, s=9.at n=17A075284
- Least positive integers, all distinct, that satisfy sum(n>0,1/a(n)^z)=0, where z=(60+I*11)/61.at n=24A084804
- Numbers k such that 8*10^k + 3 is prime.at n=7A103069
- Total sum of parts of multiplicity 1 in all partitions of n.at n=20A103628
- Triangular matchstick numbers in the class of prime numbers: sum of n-th and next n primes.at n=29A105720
- Riordan array ((1+x)/(1-2x),x(1+x)/(1-2x)).at n=50A116412
- Number of Abelian cubes of length 3n over an alphabet of size 3. An Abelian cube is a string of the form x x' x'' with |x| = |x'| = |x''| and x is a permutation of x' and x''.at n=4A141057
- Number of n X n binary arrays with rows and columns, considered as binary numbers, in nondecreasing order, and no more than 3 ones in any row or column.at n=4A162045
- Indices of pentagonal pyramidal numbers which are the sum of two other such numbers: k such that A002411(k) = A002411(i)+A002411(j) for some i,j>0.at n=18A172437
- a(n) = prime(n)^2 - n.at n=21A182174
- Number of partitions of n containing a clique of size 7.at n=37A183564
- a(n) = 6*Zeta(1-n)*n*(2^n-1) - Zeta(-n)*(n+1)*(2^(n+2)-2), for n = 0 the limit is understood.at n=12A240677
- Least positive integer m such that prime(m+n) divides 2^m - 1.at n=31A248626
- Triangular array: row n gives the coefficients of the polynomial p(n,x) defined in Comments.at n=49A249251