7881
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 24
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 10944
- Proper Divisor Sum (Aliquot Sum)
- 3063
- 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
- 5040
- Möbius Function
- -1
- Radical
- 7881
- 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
- 145
- 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
- Lucky numbers that are decimal concatenations of n with n + 3.at n=10A032653
- Decimal part of cube root of n starts with 9: first term of runs.at n=18A034135
- Odd composite numbers divisible by the sum of their prime factors (counted with multiplicity).at n=25A046347
- Composite numbers divisible by the palindromic sum of their prime factors (counted with multiplicity).at n=18A046358
- Odd numbers divisible by the palindromic sum of their prime factors (counted with multiplicity).at n=5A046359
- Inverse binomial transform of A002487.at n=13A071015
- The number of 321- and 2143-avoiding permutations of length n.at n=11A088921
- Numbers k such that numerator of Bernoulli(2*k) is divisible by 37 and 59, the first two irregular primes.at n=31A092231
- Integer part of the area of consecutive prime sided isosceles triangles.at n=31A097442
- Triangle read by rows: T(n,k) is number of paths from (0,0) to (3n,0) that stay in the first quadrant (but may touch the horizontal axis), consisting of steps u=(2,1), U=(1,2), or d=(1,-1) and having k u=(2,1) steps among the steps leading to the first d step.at n=31A108440
- Number of indecomposable partitions of n.at n=31A122697
- Composite numbers that are products of distinct primes and divisible by the sum of those primes.at n=25A131647
- Numbers k = p*q*r (p, q, r prime) congruent to 0 mod p+q+r.at n=20A160394
- The odd composites c such that c=q*g*j*y/2 and q+g=j*y where q,g,j,y are distinct primes.at n=21A167629
- Inverse permutation to A190130.at n=34A190131
- a(n) = A001209(n) + 1.at n=26A196069
- Numbers which, when divided by the sum of their prime factors, give a prime number.at n=33A199013
- For any number n take the polynomial formed by the product of the terms (x-pi), where pi's are the prime factors of n. Then calculate the area between the minimum and the maximum value of the prime factors. This sequence lists the numbers for which the area is equal to zero.at n=25A203614
- Composite squarefree numbers k such that the arithmetic mean of the distinct prime factors of k is a prime p, and p divides k.at n=18A229094
- Numbers that end in (..., 128, 128, 128, ...) under the rule: next term = product of the last four digits in the sequence so far.at n=34A240967