3925
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 4898
- Proper Divisor Sum (Aliquot Sum)
- 973
- 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
- 3120
- Möbius Function
- 0
- Radical
- 785
- Omega Function (Ω)
- 3
- 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
- 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
- 25
- 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
- no
- Achilles Number
- no
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Numbers that are the sum of 2 squares in exactly 3 ways.at n=42A000443
- G.f.: -1 + Product_{k>=1} (1 + prime(k)*x^prime(k)).at n=30A002099
- a(n+1) = 1 + a( floor(n/1) ) + a( floor(n/2) ) + ... + a( floor(n/n) ).at n=31A003318
- Centered cube numbers: n^3 + (n+1)^3.at n=12A005898
- Coordination sequence T5 for Zeolite Code MFI.at n=40A008168
- Numbers k such that the continued fraction for sqrt(k) has period 13.at n=25A020352
- Numbers k such that k + sum of its prime factors = (k+1) + sum of its prime factors.at n=17A020700
- a(n) = least m such that if r and s in {1/1, 1/4, 1/7,..., 1/(3n-2)} satisfy r < s, then r < k/m < s for some integer k.at n=41A024822
- Numbers that are the sum of 2 nonzero squares in exactly 3 ways.at n=40A025286
- Numbers that are the sum of 2 distinct nonzero squares in exactly 3 ways.at n=39A025304
- a(n) = T(n,n-3), where T is the array in A026374.at n=18A026382
- a(n) = T(n,n-3), where T is the array in A026386.at n=18A026394
- Nonsquarefree k such that Pell equation x^2 - k*y^2 = -1 is soluble.at n=33A031397
- Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 13.at n=5A031601
- Numbers whose base-4 representation contains exactly four 1's and two 3's.at n=14A045131
- Number of irreducible representations of symmetric group S_n for which every matrix has determinant 1.at n=28A045923
- a(n) = a(n-1) + a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the smallest integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = a(2) = a(3) = 1.at n=40A050024
- a(n) = a(n-1) + a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1, a(2) = 2, and a(3) = 1.at n=40A050040
- a(n) = a(n-1) + a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1, a(2) = 3, and a(3) = 1.at n=40A050056
- 15-gonal (or pentadecagonal) numbers: n*(13n-11)/2.at n=25A051867