2815
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 3384
- Proper Divisor Sum (Aliquot Sum)
- 569
- 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
- 2248
- Möbius Function
- 1
- Radical
- 2815
- Omega Function (Ω)
- 2
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 159
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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 atoms in a decahedron with n shells.at n=15A004068
- a(n) = (n+3)*2^n - 1.at n=9A006589
- Numbers k such that the continued fraction for sqrt(k) has period 32.at n=42A020371
- a(n) = Sum_{k=0..floor(n/2)} A026615(n-k,k).at n=16A026625
- Numbers k such that the continued fraction for sqrt(k) has even period 2*m and the m-th term of the periodic part is 9.at n=33A031412
- Numbers whose base-4 representation has 4 fewer 0's than 3's.at n=22A031469
- Lucky numbers with size of gaps equal to 18 (upper terms).at n=20A031901
- Numbers whose set of base-7 digits is {1,3}.at n=32A032914
- Number of partitions of n into parts not of the form 19k, 19k+5 or 19k-5. Also number of partitions with at most 4 parts of size 1 and differences between parts at distance 8 are greater than 1.at n=28A035974
- Sums of 10 distinct powers of 2.at n=12A038461
- Numbers having four 3's in base 4.at n=32A043348
- Numbers whose base-7 representation contains exactly four 1's.at n=11A043400
- Numbers n such that string 6,7 occurs in the base 9 representation of n but not of n-1.at n=38A044312
- Numbers n such that string 1,5 occurs in the base 10 representation of n but not of n-1.at n=31A044347
- Numbers n such that string 7,7 occurs in the base 8 representation of n but not of n+1.at n=43A044631
- Numbers n such that string 6,7 occurs in the base 9 representation of n but not of n+1.at n=38A044693
- Numbers n such that string 1,5 occurs in the base 10 representation of n but not of n+1.at n=31A044728
- Numbers whose base-4 representation contains no 0's and exactly four 3's.at n=22A045065
- Numbers whose base-4 representation contains no 1's and exactly four 3's.at n=11A045113
- Numbers whose base-4 representation contains exactly two 2's and four 3's.at n=0A045147