1521
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 9
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 9
- Divisor Sum
- 2379
- Proper Divisor Sum (Aliquot Sum)
- 858
- 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
- 936
- Möbius Function
- 0
- Radical
- 39
- 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
- yes
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 109
- 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
- Numbers k such that k / (sum of digits of k) is a square.at n=45A001102
- Perfect powers: m^k where m > 0 and k >= 2.at n=49A001597
- Squares and cubes.at n=47A002760
- Number of rooted trees with n vertices in which vertices at the same level have the same degree.at n=45A003238
- Expansion of g.f.: (1+x^3)*(1+x^4)/((1-x)*(1-x^2)^2*(1-x^4)).at n=32A004657
- a(n) = ceiling(n*phi^9), where phi is the golden ratio, A001622.at n=20A004964
- x^3 + n*y^3 = 1 is solvable.at n=34A005988
- Unique period lengths of primes mentioned in A007615.at n=37A007498
- Erroneous version of A048798.at n=37A007914
- Product of divisors of n.at n=38A007955
- Coordination sequence T1 for Zeolite Code DOH.at n=24A008078
- Coordination sequence T3 for Zeolite Code DOH.at n=24A008080
- Coordination sequence T1 for Zeolite Code JBW.at n=26A008121
- Coordination sequence T2 for Zeolite Code MAZ.at n=27A008145
- Coordination sequence T6 for Zeolite Code MEL.at n=25A008155
- Coordination sequence T4 for Zeolite Code MTT.at n=24A008192
- Powers of 39.at n=2A009983
- a(0) = 1, a(n) = 31*n^2 + 2 for n>0.at n=7A010020
- In the prime factorization of n, increment odd powers and decrement even powers (multiplicative and self-inverse).at n=38A011262
- Numbers k such that k divides phi(k) * sigma(k).at n=46A011775