7257
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 10080
- Proper Divisor Sum (Aliquot Sum)
- 2823
- 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
- 4640
- Möbius Function
- -1
- Radical
- 7257
- 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
- 70
- 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 x^3*(5-2*x)*(1-x^3)/(1-x)^4.at n=39A000338
- Decimal part of a(n)^(1/6) starts with reversal of its integer part: first term of runs.at n=3A034312
- Sets of 4 consecutive numbers with equal number of divisors.at n=21A039665
- Numbers having four 3's in base 6.at n=24A043384
- a(n) is the first of a triple of consecutive integers, each of which is the product of three distinct primes.at n=12A066509
- Sum of odd-indexed primes.at n=39A077131
- Number of permutations satisfying -k <= p(i) - i <= r and p(i) - i not in I, i=1..n, with k=1, r=5, I={2,3}.at n=17A079960
- a(n) = least odd number such that all pairwise sums a(i) + a(j), i < j <= n, are distinct.at n=45A080430
- Numbers k such that sigma(k)*k is a triangular number.at n=23A115909
- Odd integers that do not generate monotonically decreasing infinitary aliquot sequences.at n=17A127667
- 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, -1), (1, -1, 0), (1, 0, 1), (1, 1, 0)}.at n=7A150427
- Numbers k such that k^6 - 2 and k^6 + 2 are both primes.at n=13A154938
- A sequence of triples of squarefree consecutive integers each composed of exactly three primes.at n=36A165936
- Number of 0..n arrays x(0..5) of 6 elements with zero 3rd differences.at n=47A200273
- Start of a triple of consecutive squarefree numbers each of which has exactly 3 distinct prime factors.at n=42A242606
- Number of length n+2 0..4 arrays with the sum of medians of adjacent triples multiplied by some arrangement of +-1 equal to zero.at n=3A253125
- T(n,k)=Number of length n+2 0..k arrays with the sum of medians of adjacent triples multiplied by some arrangement of +-1 equal to zero.at n=24A253129
- Number of length 4+2 0..n arrays with the sum of medians of adjacent triples multiplied by some arrangement of +-1 equal to zero.at n=3A253132
- Total number of congruence subgroups of PSL(2,Z) of genus n.at n=4A258691
- Number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 771", based on the 5-celled von Neumann neighborhood.at n=45A273499