1635
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
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 2640
- Proper Divisor Sum (Aliquot Sum)
- 1005
- 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
- 864
- Möbius Function
- -1
- Radical
- 1635
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 42
- 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 partitions of 3n-1 into n nonnegative integers each no more than 6.at n=15A001978
- Numbers of the form (p^2 - 49)/120 where p is prime.at n=42A002382
- Josephus problem: numbers m such that, when m people are arranged on a circle and numbered 1 through m, the final survivor when we remove every 4th person is one of the first three people.at n=20A005427
- Numbers m such that 4*3^m + 1 is prime.at n=13A005537
- a(n) = 1 + n/2 + 9*n^2/2.at n=19A006137
- a(n) = a(n-1) + a(n - 1 - number of even terms so far).at n=28A006336
- Coordination sequence T1 for Zeolite Code AFG.at n=28A008012
- Expansion of e.g.f.: exp(arcsin(x)*exp(x)).at n=6A012316
- Number of ordered triples of integers from [ 1..n ] with no global factor.at n=21A015631
- Place where n-th 1 occurs in A023123.at n=34A022785
- Convolution of A023532 and A000201.at n=49A023602
- a(n) = [ (3rd elementary symmetric function of S(n))/(first elementary symmetric function of S(n)) ], where S(n) = {first n+2 odd positive integers}.at n=8A024202
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = (Fibonacci numbers), t = (composite numbers).at n=16A024461
- Index of 4^n within the sequence of the numbers of the form 3^i*4^j.at n=50A025701
- "EFK" (unordered, size, unlabeled) transform of 2,1,1,1,...at n=40A032303
- Decimal part of a(n)^(1/5) starts with a 'nine digits' anagram.at n=1A034280
- Number of partitions of n into parts 5k+1 and 5k+2 with at least one part of each type.at n=45A035631
- Number of n-node rooted identity trees of height at most 4.at n=40A038083
- Number of n-node rooted identity trees of height 4.at n=36A038088
- Sum of first n primes of form 4k+1.at n=18A038346