12774
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 25560
- Proper Divisor Sum (Aliquot Sum)
- 12786
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- yes
Derived Values
- Euler's Totient
- 4256
- Möbius Function
- -1
- Radical
- 12774
- 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
- 37
- 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
- yes
- Odd
- no
Appears in sequences
- a(n) = 1*t(n) + 2*t(n-1) + ... + k*t(n+1-k), where k=floor((n+1)/2) and t = A002808 (composite numbers).at n=45A023863
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (natural numbers), t = (composite numbers).at n=44A024860
- Denominators of continued fraction convergents to sqrt(831).at n=13A042605
- Number of ways to write the n-th prime as a sum of distinct primes.at n=51A070215
- Number of partitions of n into parts but with two kinds of parts of sizes 1,2,3,4 and 5.at n=19A103924
- Numbers k such that tau(k) = tau(k+1) mod 691, where tau is Ramanujan's tau function A000594.at n=17A121733
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (-1, 1, -1), (1, -1, 0), (1, 1, 0), (1, 1, 1)}.at n=7A150912
- Number of n-digit numbers in a cycle (including fixed points) under the Kaprekar map A151949.at n=47A164732
- Number of -2..2 arrays x(i) of n+1 elements i=1..n+1 with set{t,u,v in 0,1}((x[i+t]+x[j+u]+x[k+v])*(-1)^(t+u+v)) having two, three, four, five, six or eight distinct values for every i,j,k<=n.at n=5A211594
- Smallest integer m such that gcd{x | sum of proper divisors of x is m} is equal to 2*n, when there are at least two such x's.at n=20A253303
- Numbers k such that 7*10^k - 23 is prime.at n=24A272271
- Number of nX3 0..1 arrays with every element unequal to 1, 2, 3 or 5 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.at n=6A318093
- Number of nX7 0..1 arrays with every element unequal to 1, 2, 3 or 5 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.at n=2A318097
- T(n,k)=Number of nXk 0..1 arrays with every element unequal to 1, 2, 3 or 5 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.at n=38A318098
- T(n,k)=Number of nXk 0..1 arrays with every element unequal to 1, 2, 3 or 5 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.at n=42A318098
- a(n) = abs(a(n-1) - a(n-2)) if a(n-1) and a(n-2) are both prime or both composite. a(n) = a(n-1) + a(n-2) otherwise, where a(1) = 1 and a(2) = 2 and n > 2.at n=37A341130
- a(n) = abs(a(n-1) - a(n-2)) if a(n-1) and a(n-2) are both prime or both composite. a(n) = a(n-1) + a(n-2) otherwise, where a(1) = 1 and a(2) = 2 and n > 2.at n=40A341130
- Irregular table read by rows: T(n,k) is the number of k-gons, k>=3, in a regular drawing of a complete bipartite graph where the vertex positions on each part equal the Farey series of order n.at n=44A359694
- Number of integer compositions of n whose leaders of strictly decreasing runs are weakly decreasing.at n=21A374765
- Indices where the cumulative sum of sin(2k+1)^(2k+1) reaches a record high value.at n=22A387706