15723
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 22724
- Proper Divisor Sum (Aliquot Sum)
- 7001
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 10476
- Möbius Function
- 0
- Radical
- 5241
- Omega Function (Ω)
- 3
- 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
- no
- Squarefree Number
- no
- 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 partitions of n in which no parts are multiples of 3.at n=47A000726
- Number of partitions of n into parts not of the form 19k, 19k+6 or 19k-6. Also number of partitions with at most 5 parts of size 1 and differences between parts at distance 8 are greater than 1.at n=37A035975
- a(1) = 1; a(n+1) = floor(sqrt(Sum_{k=1..n} a(k)^2)).at n=31A067859
- Smallest a(n)>2 such that all integers strictly between a(n)-n and a(n) are composite.at n=39A075741
- List of codewords in binary lexicode with Hamming distance 6 written as decimal numbers.at n=31A075934
- Perfect totient numbers.at n=22A082897
- Perfect totient numbers, omitting powers of 3.at n=14A091847
- Positive integers n such that S(n) divides n, where S(n) is the sum of the iterates of the Euler phi-function of n, that is, S(n) = phi(n)+phi(phi(n))+....+ 1.at n=45A113808
- Number of binary strings of length n with equal numbers of 00010 and 11011 substrings.at n=15A164226
- First string of 43 consecutive composite numbers.at n=39A177949
- Number of nXnXn 0..6 triangular arrays with each element x equal to the number its neighbors equal to 5,5,0,2,0,1,0 for x=0,1,2,3,4,5,6.at n=5A203121
- a(1)=1, a(n+1) = prime(a(n)+1) - a(n).at n=10A207573
- Difference between 10^n and the first prime of gap 4 > 10^n.at n=46A227432
- Numbers n such that n*prime(n) is a pandigital number containing digits 0-9 exactly once.at n=3A272552
- Where record values occur in A276781, when starting from A276781(2)=1.at n=40A276782
- a(n) is the smallest integer k > n such that (k+1)(k+2)...(2k-2n+1)/(k(k-1)...(k-n+1)) is an integer.at n=39A290791
- Starts of runs of 3 consecutive tribonacci-Niven numbers (A352089).at n=13A352091
- Starts of runs of 3 consecutive integers whose exponent of least prime factor in their prime factorization is even.at n=29A365871