2555
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 3552
- Proper Divisor Sum (Aliquot Sum)
- 997
- 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
- 1728
- Möbius Function
- -1
- Radical
- 2555
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 58
- 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
- a(n) = a(n-1) + a(n-7), with a(i) = 1 for i = 0..6.at n=38A005709
- Coordination sequence T1 for Zeolite Code BOG.at n=36A008049
- Coordination sequence T4 for Zeolite Code DOH.at n=31A008081
- Coordination sequence T3 for Zeolite Code HEU.at n=33A008118
- Coordination sequence T3 for Zeolite Code PAU.at n=37A008221
- Pisot sequence E(8,10), a(n) = floor( a(n-1)^2/a(n-2) + 1/2 ).at n=23A010916
- a(n) = n*(2*n + 3).at n=35A014106
- a(n) = prime(n)*(prime(n-1)-1)/2.at n=18A014302
- Expansion of 1/(1-x^3-x^4-x^5-x^6-x^7-x^8-x^9-x^10-x^11-x^12).at n=25A017825
- Expansion of 1/(1 - x^7 - x^8 - ...).at n=45A017901
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly five 1's.at n=25A020441
- Every prefix prime in base 6 (written in base 6).at n=19A024766
- a(n) = (d(n)-r(n))/2, where d = A026057 and r is the periodic sequence with fundamental period (0,0,1,0).at n=24A026058
- Number of partitions of n into an even number of parts, the least being 4; also, a(n+4) = number of partitions of n into an odd number of parts, each >=4.at n=57A027196
- a(n) = Sum_{k=0..m-1} T(n,k) * T(n,k+1), where m=n for n=0,1 and m=floor((n+3)/2) for n >= 2, and T given by A026022.at n=6A027295
- a(n) = n^2 + n + 5.at n=50A027690
- T(n, 2*n-3), T given by A027960.at n=22A027965
- Base 7 digits are, in order, the first n terms of the periodic sequence with initial period 1,0,3.at n=4A037593
- Coordination sequence T3 for Zeolite Code SFF.at n=33A038433
- Numbers having three 5's in base 6.at n=29A043391