1089
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
- 9
- Divisor Sum
- 1729
- Proper Divisor Sum (Aliquot Sum)
- 640
- 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
- 660
- Möbius Function
- 0
- Radical
- 33
- Omega Function (Ω)
- 4
- 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
- yes
- 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
- 44
- 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
- yes
- Achilles Number
- no
- Perfect Power
- yes
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- n followed by n^2.at n=65A000463
- Squares that are not the sum of 2 nonzero squares.at n=22A000548
- Moser-de Bruijn sequence: sums of distinct powers of 4.at n=41A000695
- 9-gonal (or enneagonal or nonagonal) numbers: a(n) = n*(7*n-5)/2.at n=18A001106
- Numbers k such that 9*k = (k written backwards), k > 0.at n=0A001232
- Number of partitions of n into at most 4 parts.at n=49A001400
- Perfect powers: m^k where m > 0 and k >= 2.at n=42A001597
- Squares and cubes.at n=40A002760
- a(n) = a(n-1) + a(n-2) - a(n-3).at n=42A002798
- Numbers that are the sum of 4 positive 5th powers.at n=17A003349
- Numbers of the form 3^i*11^j.at n=14A003597
- a(n) = n*(3*n^2 - 1)/2.at n=9A004188
- Numbers that are the sum of at most 4 positive 5th powers.at n=43A004844
- Number of ways to add n ordinals.at n=8A005348
- Erroneous version of A048798.at n=31A007914
- Product of divisors of n.at n=32A007955
- Numbers k such that k written backwards is a nontrivial multiple of k.at n=0A008919
- Let j = | i - i_written_backwards |, k = j + j_written_backwards; then k is in this sequence.at n=13A008920
- Coordination sequence T3 for Zeolite Code -CLO.at n=29A009852
- Powers of 33.at n=2A009977