13207
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 13536
- Proper Divisor Sum (Aliquot Sum)
- 329
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 12880
- Möbius Function
- 1
- Radical
- 13207
- 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
- yes
- 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
- 45
- 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(1) = 2; a(n+1) = a(n)-th nonprime, where nonprimes begin at 1.at n=36A025003
- Numbers k such that k^2 + 3*k + 1 is a palindrome.at n=23A028348
- Number of unlabeled 4-gonal cacti having n polygons.at n=8A054362
- a(n) is the smallest number such that gcd(a(n), sigma(a(n))) = n.at n=46A074391
- (Prime(prime(n))^2-1)/24.at n=25A092772
- Semiprimes k=p*q such that the polynomial (1+x)^k (mod k) has p+q nonzero terms.at n=41A116926
- Numbers k such that A098572(k) - A098572(k-1) = 2.at n=45A133497
- Pentagonal numbers (A000326) which are the sum of 2 other positive pentagonal numbers.at n=20A136117
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, -1, 1), (-1, 1, -1), (1, 0, -1), (1, 1, 1)}.at n=8A149542
- Smallest number m such that prime(n) is a factor of both m and sigma(m).at n=14A156099
- Integers of the form 4n+3 for which Sum_{i=1..u} J(i,4n+3) obtains value zero exactly 3 times, when u ranges from 1 to (4n+3). Here J(i,k) is the Jacobi symbol.at n=39A166053
- a(n) = (3*2^(n-1)-1)*(18*2^(n-1)-7).at n=5A169722
- Number of 0..10 integer arrays v[1..n] of length n with all autocorrelation values sum(i){v[i]*v[i-k]} distinct for k in 0..n-1.at n=3A171316
- Number of 0..n-1 integer arrays v[1..4] of length 4 with all autocorrelation values sum(i){v[i]*v[i-k]} distinct for k in 0..3.at n=10A171355
- Number of ordered triples (w,x,y) with all terms in {1,...,n} and 2w^2<=x^2+y^2.at n=28A211806
- n! mod n^3.at n=46A242427
- Number of n-node rooted identity trees with thinning limbs and root outdegree (branching factor) 9.at n=6A245128
- Semiprimes of the form n*(3*n-1)/2.at n=15A245365
- Least multiple of n whose sum of divisors is divisible by n.at n=46A272349
- Array read by antidiagonals: T(n,k) is the number of noncrossing partitions up to rotation composed of n blocks of size k.at n=74A303694