12045
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 21312
- Proper Divisor Sum (Aliquot Sum)
- 9267
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 5760
- Möbius Function
- 1
- Radical
- 12045
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 4
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
- 42
- 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
- no
- Odd
- yes
Appears in sequences
- Expansion of 1/((1-5x)(1-6x)(1-10x)(1-12x)).at n=3A028178
- Triangle read by rows: number of 0-1-2 trees (i.e., ordered trees with vertices of outdegrees 0, 1, or 2) with n edges and exactly k vertices that have 2 children, both being leaves (n >= 0, 0 <= k <= floor((n+2)/4)).at n=40A126191
- Indices k such that the (k+1)-st partial sum of primes divided by k is an integer.at n=12A134126
- Expansion of q * (psi(q^5) / psi(q))^2 in powers of q where psi() is a Ramanujan theta function.at n=26A138519
- a(n) = n*(2*n^2 + 5*n + 17)/2.at n=22A163661
- a(1)=4. a(n) = a(n-1) + n, if a(n-1)+n is composite. Otherwise a(n) = a(n-1)*n.at n=23A175459
- Numbers n such that 6n and 12n are both the average of twin prime pairs.at n=21A177680
- Expansion of q * (psi(-q^5) / psi(-q))^2 in powers of q where psi() is a Ramanujan theta function.at n=26A210458
- Total number of smallest parts that are also emergent parts in all partitions of n.at n=39A220479
- Number of nonnegative integer arrays of length n summing to n without equal adjacent values modulo 3.at n=12A221316
- Expansion of 1 + q * (psi(-q^5) / psi(-q))^2 in powers of q where psi() is a Ramanujan theta function.at n=27A228864
- Triangle, read by rows, that transforms diagonals in the table of coefficients in the successive iterations of g.f. of A236960 such that column 0 equals T(n,0) = n^n.at n=40A236961
- a(n) is the smallest n-digit number whose truncation after its first k digits is divisible by the k-th Lucas number (A000032(n)) for k = 1..n.at n=4A242810
- Numbers m such that each of p=6*m+1, q=6*p+1, r=6*q+1 and s=6*r+1 is prime.at n=16A263311
- Let p = n-th prime == 7 mod 8; a(n) = sum of quadratic residues mod p that are < p/2.at n=21A282039
- Expansion of Product_{k>=1} (1 + x^k)^(10^(k-1)).at n=5A343331
- Central terms of triangle A236961: a(n) = A236961(2*n,n) for n >= 0.at n=4A359716
- Expansion of Product_{k>=1} (1 + x^k) * (1 + x^(k^2)) * (1 + x^(k^3)).at n=40A369575
- Numbers k such that the sum of the first k greater of twin primes is a greater of twin prime.at n=44A376892
- Index where n first appears in A381658.at n=45A381659