1505
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 11
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 2112
- Proper Divisor Sum (Aliquot Sum)
- 607
- 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
- 1008
- Möbius Function
- -1
- Radical
- 1505
- 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
- 39
- 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
- Expansion of a modular function for Gamma_0(21).at n=15A002511
- a(n) = 1000*log_10(n) rounded down.at n=31A004225
- a(n) = 1000*log_10(n) rounded to the nearest integer.at n=31A004226
- Cald's sequence: a(n+1) = a(n) - prime(n) if that value is positive and new, otherwise a(n) + prime(n) if new, otherwise 0; start with a(1)=1.at n=105A006509
- Coordination sequence T3 for Zeolite Code LTN.at n=27A008142
- Coordination sequence T1 for Zeolite Code SGT.at n=24A008229
- Shifts 5 places right under inverse binomial transform.at n=11A010749
- a(n) = Sum_{i=0..n-1} a(i) * a(n-i), a(0) = 1, a(1) = 5.at n=6A014434
- Numbers k that divide s(k), where s(1)=1, s(j)=21*s(j-1)+j.at n=19A014872
- Odd numbers k such that phi(k) | sigma_3(k).at n=32A015809
- Powers of cube root of 23 rounded up.at n=7A018044
- Cycle class sequence c(n) (the number of true cycles of length n in which a certain node is included) for zeolite BEA = Beta Na7[Al7Si57O128] starting with a T8 atom.at n=10A019074
- a(0)=0, a(2*n) = 2*a(n) + 2*a(n-1) + n^2 + n, a(2*n+1) = 4*a(n) + (n+1)^2.at n=33A022560
- a(n) is least k such that k and 5k are anagrams in base n (written in base 10).at n=30A023097
- a(n) = least m such that if r and s in {1/2, 1/5, 1/8, ..., 1/(3n-1)} satisfy r < s, then r < k/m < (k+1)/m < s for some integer k.at n=17A024837
- a(n) = floor(floor(S3)/floor(S1)); where S3 and S1 are, respectively, the third and first elementary symmetric functions of {log(k)}, k = 1,2,...,n.at n=33A025210
- Numbers that are the sum of 3 nonzero squares in exactly 10 ways.at n=29A025330
- Numbers that are the sum of 3 distinct nonzero squares in exactly 10 ways.at n=29A025348
- Index of 10^n within the sequence of the numbers of the form 5^i*10^j.at n=45A025743
- Number of partitions of n into an odd number of parts, the greatest being 5; also, a(n+9) = number of partitions of n+4 into an even number of parts, each <=5.at n=51A026925