3123
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 9
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 4524
- Proper Divisor Sum (Aliquot Sum)
- 1401
- 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
- 2076
- Möbius Function
- 0
- Radical
- 1041
- 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
- yes
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 61
- 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
- Double-bitters: only even length runs in binary expansion.at n=37A001196
- Cycle class sequence c(n) (the number of true cycles of length n in which a certain node is included) for zeolite RUT = RUB-10 R4[B4Si32O72] starting from a T4 atom.at n=11A019231
- Ordered sequence of distinct terms of the form floor(x^i * floor(x^j)), i,j >= 0, where x = sqrt(5).at n=28A022770
- Numbers k such that Fib(k) == -34 (mod k).at n=24A023169
- n written in fractional base 5/3.at n=23A024633
- Every suffix prime and no 0 digits in base 8 (written in base 8).at n=54A024783
- Lucky numbers with size of gaps equal to 10 (lower terms).at n=37A031892
- Decimal concatenation of n-th lucky number and n-th prime number.at n=8A032604
- Number of partitions of n into parts not of form 4k+2, 24k, 24k+7 or 24k-7. Also number of partitions in which no odd part is repeated, with at most 3 parts of size less than or equal to 2 and where differences between parts at distance 5 are greater than 1 when the smallest part is odd and greater than 2 when the smallest part is even.at n=39A036032
- Maximal base 5 run length is 4.at n=35A037983
- Partial sums of primes congruent to 5 mod 6.at n=26A038361
- Conjecturally, largest attractor in '3x+(2n+1)' problem.at n=22A039515
- Numbers having four 4's in base 5.at n=19A043368
- Numbers k such that the string 2,5 occurs in the base 9 representation of k but not of k-1.at n=43A044274
- Numbers n such that string 2,3 occurs in the base 10 representation of n but not of n-1.at n=34A044355
- Numbers n such that string 2,3 occurs in the base 10 representation of n but not of n+1.at n=34A044736
- Numbers whose base-4 representation contains exactly three 0's and three 3's.at n=1A045079
- Minimal elements of pairs of "Super Unitary Amicable Numbers", sorted by their minimal elements.at n=14A045613
- a(n) = T(2n-1,n), array T given by A048225.at n=29A048234
- Sum of transposition distances (divided by 2) present in the permutation produced by inverses of 1..(p-1) computed in Zp, where p is n-th prime.at n=32A051864