13531
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- yes
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 15472
- Proper Divisor Sum (Aliquot Sum)
- 1941
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 11592
- Möbius Function
- 1
- Radical
- 13531
- 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
- 138
- 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
- a(n) = a(n-1) + a(n-2) - 1.at n=20A001588
- Numbers k such that the continued fraction for sqrt(k) has period 90.at n=30A020429
- Palindromic lucky numbers.at n=35A031161
- Lucky numbers that are both palindromic and nonprime.at n=29A031880
- Palindromic Super-2 Numbers.at n=21A032750
- Numbers having four 3's in base 8.at n=5A043436
- Palindromic and divisible by 7.at n=38A045642
- a(n+2) = a(n+1) + a(n) + (-1)^n, with a(1) = a(2) = 1.at n=21A066983
- Ulam numbers such that 2*n is also an Ulam number.at n=19A068791
- Third row of Pascal-(1,4,1) array A081579.at n=33A081587
- Smallest palindrome beginning with n and digit sum n, or 0 if no such number exists.at n=12A082217
- Palindromic time display in hours, minutes, seconds on a six spaced 24-hour digital clock, using hours 1-24.at n=35A082567
- Smallest palindrome beginning with n and a digit sum of n at some stage.at n=12A082935
- Sum of the first n primes whose indices are primes.at n=36A083186
- Palindromes with more than 3 digits in which the absolute difference of a pair of successive digits is identical.at n=14A085109
- Palindromic numbers with property that sum of digits is prime and number of prime digits is prime.at n=18A093807
- Palindromic primes in base 6 (written in base 6).at n=17A117701
- Palindromic primes in base 7 (written in base 7).at n=13A117702
- Palindromic primes in base 9 (written in base 9).at n=21A117703
- Palindromic composites such that some digit permutation is prime.at n=30A119378