6903
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 10920
- Proper Divisor Sum (Aliquot Sum)
- 4017
- 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
- 4176
- Möbius Function
- 0
- Radical
- 2301
- Omega Function (Ω)
- 4
- 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
- yes
- 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
- 57
- 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
- a(n) = (2*n+1)*(4*n+1).at n=29A014634
- a(n+1) = Sum_{k=0..floor(3*n/5)} a(k) * a(n-k).at n=14A030038
- n plus a googol is prime.at n=20A049014
- a(n) = n*(2*n+5)*(n-1)/6.at n=27A051925
- n satisfying sigma(n+1) = sigma(n-1).at n=15A055574
- a(n) = 25*n*(n + 1)/2 + 3.at n=23A061793
- Numbers k such that sigma(k-1) divides sigma(k+1).at n=19A067130
- Triangular numbers which are a concatenation of two or more positive triangular numbers.at n=20A068144
- Triangular numbers with property that digits alternate in parity.at n=23A068882
- Triangular numbers with property that digits alternate in parity individually as well as in concatenation with previous terms.at n=15A068889
- Centered 17-gonal numbers: (17*n^2 - 17*n + 2)/2.at n=28A069130
- Triangular numbers whose sum of prime factors (with repetition) is also triangular.at n=12A076169
- Triangular numbers which are 4-almost primes.at n=32A076578
- Triangular numbers using only the curved digits 0, 3, 6, 8 and 9.at n=11A079653
- Staggered diagonal of triangular spiral in A051682.at n=39A081266
- Third row of Pascal-(1,6,1) array A081581.at n=17A081591
- Triangular numbers in which the sum of the external digits equals the sum of the internal digits.at n=8A088289
- 47-gonal numbers.at n=17A095311
- A Chebyshev transform of Fib(2n+2).at n=11A099444
- a(1)=1. a(n) = a(n-1) + sum of the squares which are among the first (n-1) terms of the sequence.at n=30A101135