15530
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 27972
- Proper Divisor Sum (Aliquot Sum)
- 12442
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6208
- Möbius Function
- -1
- Radical
- 15530
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 102
- 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
- yes
- Odd
- no
Appears in sequences
- a(n) = sigma_3(n) - sigma_2(n).at n=23A092349
- Numbers n such that 5*10^n + 4*R_n + 3 is prime, where R_n = 11...1 is the repunit (A002275) of length n.at n=15A103015
- 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, 1), (-1, 1, 0), (-1, 1, 1), (0, 0, 1), (1, 0, -1)}.at n=10A148300
- 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, 0, 0), (0, 0, 1), (1, -1, 0), (1, 1, -1), (1, 1, 1)}.at n=7A150890
- a(n) is the least k such that for numbers x >= k, PrimePi(n,x) > PrimePi(n-1,x), where PrimePi(n,x) is the number of n-almost-primes <= x.at n=2A180126
- Number of fixed tree-like convex polyominoes.at n=11A196593
- Number of compositions of n where the difference between largest and smallest parts equals 4 and adjacent parts are unequal.at n=16A214273
- Expansion of psi(x^4) / f(-x) in powers of x where psi(), f() are Ramanujan theta functions.at n=33A226635
- Let s(n,j) be Sum_{i=1..j} (prime(primepi(n) + i) mod n). Numbers n such that there exists j with s(n,j) = n.at n=35A274423
- Number of length-n binary strings where every prefix is either a palindrome, or the concatenation of two palindromes.at n=51A297702
- The successive approximations up to 7^n for 7-adic integer 2^(1/5).at n=5A309450
- Expansion of Product_{i>=1, j>=1, k>=1} 1/(1 - x^(i*j*k))^(i*j*k).at n=10A318413
- Numbers k with Goldbach partitions (p,q) and (r,s) such that k | (p*q -1) and k | (r*s +1).at n=2A336584