1045
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 10
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 1440
- Proper Divisor Sum (Aliquot Sum)
- 395
- 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
- 720
- Möbius Function
- -1
- Radical
- 1045
- 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
- 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
- 31
- 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
- Octagonal numbers: n*(3*n-2). Also called star numbers.at n=19A000567
- Moser-de Bruijn sequence: sums of distinct powers of 4.at n=39A000695
- Generalized octagonal numbers: k*(3*k-2), k=0, +- 1, +- 2, +-3, ...at n=37A001082
- a(n) is the solution to the postage stamp problem with 6 denominations and n stamps.at n=7A001211
- Octagonal pyramidal numbers: a(n) = n*(n+1)*(2*n-1)/2.at n=9A002414
- Odd squarefree numbers with an odd number of prime factors that have no prime factors greater than 31.at n=44A002556
- Numbers k such that (k^2 + k + 1)/21 is prime.at n=46A002644
- Numbers that are a sum of distinct positive cubes in more than one way.at n=42A003998
- a(n) = n*(n + 1)*(n^2 - 3*n + 6)/8.at n=9A004255
- a(n) = floor(Fibonacci(n)/4).at n=19A004697
- a(n) = floor(n*phi^7), where phi is the golden ratio, A001622.at n=36A004922
- a(n) = round(n*phi^7), where phi is the golden ratio, A001622.at n=36A004942
- a(n) = solution to the postage stamp problem with n denominations and 8 stamps.at n=5A005343
- 4-dimensional analog of centered polygonal numbers: a(n) = n(n+1)*(n^2+n+4)/12.at n=10A006007
- Related to representations as sums of Fibonacci numbers.at n=19A006133
- Numbers n such that n! has a square number of digits.at n=25A006488
- Triangular numbers plus quarter squares: n*(n+1)/2 + floor(n^2/4) (i.e., A000217(n) + A002620(n)).at n=37A006578
- Number of strict 3rd-order maximal independent sets in path graph.at n=32A007384
- Coordination sequence T10 for Zeolite Code EUO.at n=20A008096
- Coordination sequence T4 for Zeolite Code EUO.at n=20A008099