6123
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 8848
- Proper Divisor Sum (Aliquot Sum)
- 2725
- 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
- 3744
- Möbius Function
- -1
- Radical
- 6123
- Omega Function (Ω)
- 3
- 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
- 186
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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) = n*(4*n+1).at n=39A007742
- Numbers k that divide s(k), where s(1)=1, s(j)=9*s(j-1)+j.at n=28A014857
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (Fibonacci numbers), t = (primes).at n=19A025088
- a(n) = T(2n-1,n), where T is the array in A026098.at n=36A026102
- Lucky numbers with size of gaps equal to 18 (lower terms).at n=35A031900
- Numbers whose base-5 representation contains exactly two 3's and three 4's.at n=16A045303
- Numbers k that divide 7^k + 2^k.at n=24A045580
- Numbers k that divide 7^k + 5^k.at n=20A045596
- McKay-Thompson series of class 15C for Monster.at n=14A058510
- Composite n such that the sums of the composite numbers up to n, +/- 1, are twin primes.at n=37A065022
- Sum of the quadratic residues of prime(n).at n=36A076409
- Least positive integers, all distinct, that satisfy sum(n>0,1/a(n)^z)=0, where z=(60+I*11)/61.at n=9A084804
- a(1) = 1 and then least squarefree number such that every partial concatenation of 2 or more terms is a prime.at n=40A086475
- a(n) = smallest k where (10^k+1)=0 mod prime(n)^2, or 0 if no such k exists.at n=36A086981
- Number of partitions of n-set with 2 block sizes.at n=6A088142
- Binomial transform of tau(n) (see A000005).at n=11A101509
- Smaller of two consecutive lucky numbers with the same digital sum.at n=21A118566
- Where record values of A119999 occur.at n=27A120001
- Number of 4-ary Lyndon words of length n with exactly five 1s.at n=4A124813
- Triangle of number of 4-ary Lyndon words of length n containing exactly k 1s.at n=60A124814