15706
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 23562
- Proper Divisor Sum (Aliquot Sum)
- 7856
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7852
- Möbius Function
- 1
- Radical
- 15706
- 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
- 84
- 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
- a(n) = Sum_{k=0..n} C(n-k,4*k).at n=18A005676
- Numbers k such that the continued fraction for sqrt(k) has period 81.at n=14A020420
- Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 27.at n=3A031615
- Numbers whose base-5 representation contains exactly three 0's and three 1's.at n=17A045172
- Numbers k such that 297*2^k-1 is prime.at n=38A050907
- Numbers k such that 2*6^k - 1 is prime.at n=38A057472
- First string of 43 consecutive composite numbers.at n=22A177949
- Number of (w,x,y,z) with all terms in {1,...,n} and |w-x|=2|x-y|+2|y-z|.at n=40A212576
- Total number of parts of multiplicity 7 in all partitions of n.at n=42A222707
- Numbers of the form 5^j + 9^k, for j and k >= 0.at n=32A226829
- Andrews's shadow difference function D_3(q).at n=40A275633
- Numbers of the form a^4 + b^6, with integers a, b > 0.at n=44A303374
- a(n) = 36*n^2 - 8*n - 2 (n >=1).at n=20A304834
- Number of compositions (ordered partitions) of n into at most 5 squarefree parts.at n=39A347780
- The number of days elapsed since the Gregorian (proleptic) date Sunday, December 31, 1 BC on 1/1/n, where 1/1/n is the Gregorian date in the format month/day/year, the New Year's Day of the year n.at n=43A350471
- a(n) = Sum_{k=1..n} k * rad(k).at n=38A350996
- Number of compositions of 5*n-3 into parts 4 and 5.at n=14A369851
- Numbers of the form h^i + k^j where h,i,j,k are distinct positive integers and max{h,i,j,k} - min{h,i,j,k} = 3.at n=32A391670
- a(n) = Sum_{k=0..floor(n/2)} binomial(k,2*(n-2*k)).at n=36A392250