505
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 10
- Digital Root
- 1
- Palindromic Number
- yes
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 612
- Proper Divisor Sum (Aliquot Sum)
- 107
- 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
- 400
- Möbius Function
- 1
- Radical
- 505
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 61
- 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
- fünfhundertfünf· ordinal: fünfhundertfünfste
- English
- five hundred five· ordinal: five hundred fifth
- Spanish
- quinientos cinco· ordinal: 505º
- French
- cinq cent cinq· ordinal: cinq cent cinqième
- Italian
- cinquecentocinque· ordinal: 505º
- Latin
- quingenti quinque· ordinal: 505.
- Portuguese
- quinhentos e cinco· ordinal: 505º
Appears in sequences
- Numbers m such that Fibonacci(m) ends with m.at n=20A000350
- Number of twin prime pairs < square of n-th prime.at n=41A000885
- Primes multiplied by 5.at n=25A001750
- Palindromes in base 10.at n=59A002113
- Roman numerals with 1 letter, in numerical order; then those with 2 letters, etc.at n=26A003587
- Roman numerals with 1 letter, in alphabetical order; then those with 2 letters, etc.at n=17A003588
- Add 4, then reverse digits; start with 0.at n=16A003608
- Add 4, then reverse digits; start with 0.at n=70A003608
- Sum of remainders of n mod k, for k = 1, 2, 3, ..., n.at n=52A004125
- a(n) = ceiling(100*log_2(n)).at n=32A004264
- Divisible only by primes congruent to 5 mod 8.at n=36A004627
- Expansion of e.g.f. 1/(6-exp(x)-exp(2*x)-exp(3*x)-exp(4*x)-exp(5*x)).at n=2A004703
- Sum of digits of n-th term in Look and Say sequence A005150.at n=19A004977
- Shifts one place left under 6th-order binomial transform.at n=4A005012
- a(n) = n*(n^2 + 1)/2.at n=10A006003
- Site percolation series for square lattice.at n=12A006731
- Number of partitions of n into partition numbers.at n=28A007279
- Add 2, then reverse digits!.at n=23A007396
- Numbers that are the sum of 2 nonzero squares in 2 or more ways.at n=31A007692
- Expansion of (x^6-x^5-x^4+2x^2)/((1-x^3)(1-x^2)^2(1-x)).at n=28A007988