9591
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 24
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 13440
- Proper Divisor Sum (Aliquot Sum)
- 3849
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6072
- Möbius Function
- -1
- Radical
- 9591
- 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
- yes
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 166
- 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
- a(n) = p*(p-1)/2 for p = prime(n).at n=33A008837
- a(n) = (2*n-1)*(4*n-1).at n=35A033567
- Numbers k such that the smoothly undulating palindromic number (37*10^k - 73)/99 is a prime.at n=8A062219
- Triangular numbers with arithmetic mean of digits = integer (sum of digits = A multiple of the number of digits).at n=41A069712
- One-sixth the area of the smallest primitive d-arithmetic triangle, where d=A072330(n).at n=28A072360
- Smallest multiple of (n+1)-st prime which is == 1 mod n-th prime.at n=32A073604
- Products of members of pairs in A075333.at n=23A075337
- Triangular numbers that are 3-almost primes.at n=40A075875
- Triangular numbers which are also happy numbers (cf. A007770).at n=18A076712
- Positive integers not expressible as the sum of a prime and a triangular number.at n=56A076768
- Triangular numbers whose external digits form a triangular number. Or triangular number whose MSD and LSD form a triangular number.at n=42A077367
- a(n) = (25*n^2 - 15*n + 2)/2.at n=28A080857
- Third row of Pascal-(1,6,1) array A081581.at n=20A081591
- a(n) = p(n)*(p(n)-1)/2 where p(n) = upper member of n-th pair of twin primes.at n=10A082669
- a(n) = T(n) concatenated with reverse(T(n)) divided by 11, where T(n) is the n-th triangular number.at n=14A084008
- Numbers n such that nextprime(n^3)-prevprime(n^3) = 4.at n=44A090121
- Row sums of triangle A093922.at n=14A093925
- a(n) = A104908(n) - 100*A104803(n).at n=21A104910
- Least triangular number divisible by n-th prime.at n=33A112456
- Triangular numbers whose digit reversal is a semiprime (A001358).at n=41A115742