1491
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 2304
- Proper Divisor Sum (Aliquot Sum)
- 813
- 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
- 840
- Möbius Function
- -1
- Radical
- 1491
- 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
- 91
- 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
- Number of nonnegative solutions to x^2 + y^2 <= n^2.at n=43A000603
- 9-gonal (or enneagonal or nonagonal) numbers: a(n) = n*(7*n-5)/2.at n=21A001106
- a(n) = 1000*log_10(n) rounded down.at n=30A004225
- a(n) = 1000*log_10(n) rounded to the nearest integer.at n=30A004226
- Exponent of least power of 2 having n consecutive 0's in its decimal representation.at n=5A006889
- Number of non-Abelian metacyclic groups of order p^n (p odd).at n=43A007983
- Coordination sequence T2 for Zeolite Code TON.at n=24A008242
- Powers of fifth root of 21 rounded up.at n=12A018176
- Pseudoprimes to base 76.at n=29A020204
- Pseudoprimes to base 85.at n=22A020213
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly nine 1's.at n=3A020445
- Convolution of natural numbers with Beatty sequence for the golden mean A000201.at n=16A023541
- Index of 9^n within the sequence of the numbers of the form 2^i*9^j.at n=30A025734
- a(n) = T(2n-1,n), where T is the array in A026098.at n=19A026102
- Sum of the numbers between the two n's in A026362.at n=20A026365
- a(n) = n^2 + n + 9.at n=38A027694
- Iterate the map in A006369 starting at 8.at n=47A028394
- Odd 9-gonal (or enneagonal) numbers.at n=10A028991
- Number of words of length 4 in the n(n-1)/2 transpositions of S[ n ] equivalent to the identity.at n=6A029699
- Numbers k such that k-2 and k+2 are consecutive primes.at n=51A029708