7125
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 12480
- Proper Divisor Sum (Aliquot Sum)
- 5355
- 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
- 3600
- Möbius Function
- 0
- Radical
- 285
- Omega Function (Ω)
- 5
- 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
- yes
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 75
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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(n) = n*(n+1)*(n+2)*(n+7)/24.at n=18A005582
- Coordination sequence T2 for Coesite.at n=45A008268
- Odd numbers to the left of the central elements of the (1,2)-Pascal triangle A029635.at n=51A029646
- Odd numbers to the right of the central elements of the (2,1)-Pascal triangle A029653 that are different from 1.at n=30A029668
- a(0)=2; a(n) is the smallest k > a(n-1) such that the fractional part of k^(1/11) starts with n.at n=24A034076
- Number of partitions of n into parts not of the form 19k, 19k+5 or 19k-5. Also number of partitions with at most 4 parts of size 1 and differences between parts at distance 8 are greater than 1.at n=33A035974
- Positive numbers having the same set of digits in base 8 and base 10.at n=31A037442
- Numbers k that divide 8^k + 7^k.at n=48A045604
- Smallest k such that d(phi(k)) - phi(d(k)) = n, where d(k) = A000005(k) and phi(k) = A000010(k).at n=36A078150
- Hypotenuses for which there exist exactly 3 distinct integer triangles.at n=38A084647
- Numbers n such that nextprime(n^3)-prevprime(n^3) = 4.at n=34A090121
- Number of 4k+3 primes whose Legendre-vector is not Dyck-path (A095103) in range ]2^n,2^(n+1)].at n=17A095093
- a(1)=1. a(n) = n*a(n-1) if n*a(n-1) has a fewer number of divisors than n+a(n-1) does. a(n) = n+a(n-1) if n*a(n-1) has a greater or equal number of divisors than n+a(n-1) does.at n=13A134190
- a(n) = smallest number m which without its leftmost digit is equal to m/n (or 0 if no such number exists).at n=55A141027
- Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 111-110-111 pattern in any orientation.at n=14A146286
- 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, -1, 1), (0, 1, -1), (1, -1, 1), (1, 1, 1)}.at n=7A149786
- Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of n steps taken from {(-1, -1), (0, -1), (0, 1), (1, 0)}.at n=10A151395
- Number of nX2 1..5 arrays containing at least one of each value, all equal values connected, rows considered as a single number in nondecreasing order, and columns considered as a single number in nonincreasing order.at n=5A166827
- Partial sums of A045542.at n=32A177955
- Numbers k such that (k^3 - 2, k^3 + 2) is a pair of cousin primes (see A178227).at n=33A178228