12155
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 18144
- Proper Divisor Sum (Aliquot Sum)
- 5989
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7680
- Möbius Function
- 1
- Radical
- 12155
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 4
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
- 187
- 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
- Number of compositions of n into 5 ordered relatively prime parts.at n=21A000743
- Numerators in expansion of 1/sqrt(1-x).at n=9A001790
- Least integer having Radon random number n.at n=15A002661
- Numerator of n!!/(n+1)!! (cf. A006882).at n=17A004730
- Numerator of average distance traveled by n-dimensional fly.at n=16A004734
- Triangle of coefficients of Legendre polynomials P_n (x).at n=29A008316
- Nearest integer to (n/2)^4.at n=21A011863
- a(n) = n*(21*n + 1)/2.at n=34A022279
- a(n) is least k such that k and 9k are anagrams in base n (written in base 10).at n=11A023101
- a(n) = greatest residue of S(n,m) mod C(n-1,m-1), for m = 1,2,...,n; S(n,m) are Stirling numbers of second kind.at n=17A024424
- Denominator of rational part of Haar measure on Grassmannian space G(n,1).at n=18A036069
- Numbers n such that 229*2^n-1 is prime.at n=32A050866
- (Terms in A014476)/2.at n=31A051497
- Numerators in the Taylor series for arccosh(x) - log(2*x).at n=8A052468
- Squarefree part of n!: n! divided by its largest square divisor.at n=17A055204
- Numerators of Taylor series expansion of arcsin(x). Also arises from arccos(x), arccsc(x), arcsec(x), arcsinh(x).at n=9A055786
- Squarefree part of the n-th central binomial coefficient.at n=17A056058
- The powerfree part of the central binomial coefficients.at n=17A056060
- Bisection of A001790.at n=4A063079
- Composite numbers k with no prime factor among (2, 3) (cf. A038509) and such that phi(k) < 2*k/3.at n=36A069043