12746
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 19122
- Proper Divisor Sum (Aliquot Sum)
- 6376
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6372
- Möbius Function
- 1
- Radical
- 12746
- Omega Function (Ω)
- 2
- 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
- 125
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- yes
- Odd
- no
Appears in sequences
- Concatenate n-th prime and n-th composite.at n=30A038530
- One third of the sum of the first n primes, when an integer.at n=38A112270
- Triangle read by rows: T(n,k) is the number of Dyck paths of semilength n having k ascents of length 2 starting at an even level (0<=k<=floor(n/2)).at n=38A114462
- Triangle read by rows: T(n,k) is the number of ternary words of length n on {0,1,2} having sum of the lengths of the drops equal to k (n>=0, k>=0). The drops of a ternary word on {0,1,2} are the subwords 10,20 and 21, their lengths being the differences 1, 2 and 1, respectively.at n=55A120907
- Has two properties: concatenation of its digits is same string as concatenation of digits of its first differences and every number appears exactly one of the sequence or its first differences.at n=44A139310
- Minimal exponents m such that the fractional part of (10/9)^m obtains a maximum (when starting with m=1).at n=14A153695
- Numbers k such that the fractional part of (10/9)^k is greater than 1-(1/k).at n=5A153696
- Number of compositions of n having exactly nine fixed points.at n=13A240744
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 165", based on the 5-celled von Neumann neighborhood.at n=26A270459
- Expansion of Product_{k>=1} 1/(1-x^(k^2))^(k^2).at n=35A291655
- Number of permutations on [n] whose up-down signature has nonnegative partial sums and which have exactly two descents.at n=8A321268
- Number T(n,k) of permutations p of [n] with exactly k descents such that the up-down signature of p has nonnegative partial sums; triangle T(n,k), n>=0, 0<=k<=max(0,floor((n-1)/2)), read by rows.at n=23A321280
- Total number of parts coprime to n in the partitions of n into 10 parts.at n=34A363328
- G.f.: Sum_{k>=0} x^k * Product_{j=1..5*k} (1 + x^j).at n=47A385069