12145
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 16704
- Proper Divisor Sum (Aliquot Sum)
- 4559
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8304
- Möbius Function
- -1
- Radical
- 12145
- 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
- 63
- 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
- Expansion of e.g.f. tan(x)/cos(sin(x)), odd powers only.at n=4A009755
- exp(arcsin(x)-log(x+1))=1+1/2!*x^2-1/3!*x^3+9/4!*x^4-25/5!*x^5...at n=8A013397
- Odd heptagonal numbers (A000566).at n=35A014637
- Numbers k such that the continued fraction for sqrt(k) has period 86.at n=33A020425
- a(n) = least m such that if r and s in {1/1, 1/3, 1/5, ..., 1/(2n-1)} satisfy r < s, then r < k/m < (k+4)/m < s for some integer k.at n=36A024847
- a(n) = n^3 - n + 1.at n=23A061600
- Centered 23-gonal numbers.at n=32A069174
- The last number for which a determinant of base-n numbers is nonzero.at n=21A079505
- Number of comparisons required to create all permutations of n distinct elements using the "streamlined" version of Algorithm L (lexicographic permutation generation) from Knuth's The Art of Computer Programming, Vol. 4, chapter 7.2.1.2.at n=4A079884
- Number of symmetric sum-free subsets of {1,2,...,n-1} with sums taken mod n.at n=48A083041
- Sum of largest parts (counted with multiplicity) of all partitions of n into odd parts.at n=36A092310
- a(n) = (3+n)*(2 + 33*n + n^2)/6.at n=32A101860
- Heptagonal numbers divisible by 7.at n=20A117795
- Partial sums of A027444.at n=14A152457
- Numbers k such that k^2 + 1 == 0 (mod 41^2).at n=14A157116
- Products of 3 distinct safe primes.at n=28A157354
- E.g.f. A(x) satisfies: A'(x) = (1 - sqrt(1-4*A(x))) / (2*A(x)).at n=5A180254
- a(n) = n*(10*n-3).at n=35A195018
- Centered 44-gonal numbers.at n=23A195318
- Number of (n+1) X (1+1) 0..2 arrays with no 2 X 2 subblock having a diagonal absolute difference less than its antidiagonal absolute difference.at n=3A250834