1845
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
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 3276
- Proper Divisor Sum (Aliquot Sum)
- 1431
- 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
- 960
- Möbius Function
- 0
- Radical
- 615
- 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
- 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
- 37
- 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
- Smallest k such that the product of q/(q-1) over the primes from prime(n) to prime(n+k-1) is greater than 2.at n=29A001276
- a(n) = 4*a(n-1) - a(n-2) + 1, with a(0) = 0, a(1) = 2.at n=6A001571
- a(n) = Sum_{k=0..n} f(k)*f(n-k) where f(k) = A002124(k).at n=28A002125
- Max_{k=0..n} { Number of partitions of n into exactly k parts }.at n=36A002569
- a(n) = (4*n+1)*(4*n+5).at n=10A003185
- Numbers that are the sum of 11 positive 6th powers.at n=29A003367
- a(n) = round(n*phi^10), where phi is the golden ratio, A001622.at n=15A004945
- a(n) = ceiling(n*phi^10), where phi is the golden ratio, A001622.at n=15A004965
- a(n) = least integer m > a(n-1) such that m - a(n-1) != a(j) - a(k) for all j, k less than n; a(1) = 1, a(2) = 2.at n=41A004978
- Number of Twopins positions.at n=16A005687
- a(n) = floor(n*(n+2)*(2*n-1)/8).at n=18A007518
- Coordination sequence T4 for Zeolite Code DDR.at n=27A008074
- Molien series for A_9.at n=27A008632
- Number of partitions of n into at most 9 parts.at n=27A008638
- Expansion of e.g.f. theta_3^(5/2).at n=5A015666
- Pseudoprimes to base 73.at n=30A020201
- Pseudoprimes to base 91.at n=25A020219
- Numbers that are the sum of 3 distinct nonzero squares in exactly 9 ways.at n=29A025347
- a(n) = sum of the numbers between the two n's in A026242.at n=40A026271
- a(n) = position of the n-th n in A026409.at n=39A026412