655
domain: N
Properties
Digital Properties
- Digit Count
- 3
- 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
- 792
- Proper Divisor Sum (Aliquot Sum)
- 137
- 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
- 520
- Möbius Function
- 1
- Radical
- 655
- 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
- 144
- Smith 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
Names
- German
- sechshundertfünfundfünfzig· ordinal: sechshundertfünfundfünfzigste
- English
- six hundred fifty-five· ordinal: six hundred fifty-fifth
- Spanish
- seiscientos cincuenta y cinco· ordinal: 655º
- French
- six cent cinquante-cinq· ordinal: six cent cinquante-cinqième
- Italian
- seicentocinquantacinque· ordinal: 655º
- Latin
- sescenti quinquaginta quinque· ordinal: 655.
- Portuguese
- seiscentos e cinquenta e cinco· ordinal: 655º
Appears in sequences
- Primes multiplied by 5.at n=31A001750
- a(1) = 0, a(2) = 0; for n > 2, a(n) - a(n-3) - a(n-5) - ... - a(n-p) = n if n is prime, otherwise = 0, where p = largest prime < n.at n=24A002123
- Divisible only by primes congruent to 5 mod 7.at n=31A004623
- a(n)=least number m such that m-a(n-1)<>a(j)-a(k) for all j,k less than m; a(1)=1, a(2)=3.at n=25A004979
- a(n) = 1 + n/2 + 9*n^2/2.at n=12A006137
- Coordination sequence T1 for Zeolite Code BOG.at n=18A008049
- Coordination sequence T1 for Zeolite Code LEV.at n=19A008127
- Expansion of Jacobi theta constant theta_2^5 /32.at n=40A008439
- Coordination sequence T1 for Zeolite Code iRON.at n=18A009881
- a(n) = floor(n*(n-1)*(n-2)/30).at n=28A011912
- Expansion of 1/(1 - x^10 - x^11 - ...).at n=51A017904
- Cycle class sequence c(n) (the number of true cycles of length n in which a certain node is included) for zeolite VET = VPI-8 [Si17O34] starting with a T2 atom.at n=9A019248
- Continued fraction for tan(1/9).at n=73A019432
- Numbers k such that the continued fraction for sqrt(k) has period 16.at n=26A020355
- a(n) = n*(13*n + 1)/2.at n=10A022271
- Numbers k such that Fibonacci(k) == 5 (mod k).at n=28A023176
- Convolution of A023531 and A001950.at n=49A023564
- Convolution of Fibonacci numbers and {F(2), F(3), F(4), ...}.at n=9A023610
- Numbers with exactly 3 1's in base 5 expansion.at n=18A023728
- a(n) = floor((4th elementary symmetric function of S(n))/(3rd elementary symmetric function of S(n))), where S(n) = {first n+3 positive integers congruent to 1 mod 3}.at n=40A024224