8125
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 10
- Divisor Sum
- 10934
- Proper Divisor Sum (Aliquot Sum)
- 2809
- 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
- 6000
- Möbius Function
- 0
- Radical
- 65
- Omega Function (Ω)
- 5
- Little Omega Function (ω)
- 2
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
- no
- Narcissistic Number
- no
- Collatz Steps
- 65
- 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
- Pentagonal pyramidal numbers: a(n) = n^2*(n+1)/2.at n=25A002411
- Odd pentagonal pyramidal numbers.at n=6A015223
- Least positive integer that is the sum of two squares of positive integers in exactly n ways.at n=4A016032
- Smallest k such that circle x^2 + y^2 = k passes through exactly 4n integer points.at n=9A018782
- a(n) = ((5+sqrt(5))/2)^n + ((5-sqrt(5))/2)^n.at n=7A020876
- Numbers that are the sum of 2 nonzero squares in exactly 5 ways.at n=0A025288
- Numbers that are the sum of 2 nonzero squares in 5 or more ways.at n=1A025296
- Numbers that are the sum of 2 distinct nonzero squares in exactly 5 ways.at n=0A025306
- Numbers that are the sum of 2 distinct nonzero squares in 5 or more ways.at n=1A025315
- 5-automorphic numbers: final digits of 5n^2 agree with n.at n=3A030988
- Digits d in decimal expansion of n replaced with d^3.at n=25A048390
- Numbers of the form q1^b1 * q2^b2 * q3^b3 * q4^b4 * q5^b5 * ... where q1=5, q2=13, q3=17, q4=29, q5=37, ... (A002144) and b1 >= b2 >= b3 >= b4 >= b5 >= ....at n=12A054994
- 5-morphic but not bimorphic, automorphic nor trimorphic.at n=41A056036
- Number of step shifted (decimated) sequences using a maximum of five different symbols.at n=5A056374
- Coefficient triangle of polynomials (falling powers) related to Fibonacci convolutions. Companion triangle to A057281.at n=28A057282
- Numbers n such that n | 11^n + 10^n + 9^n + 8^n + 7^n + 6^n + 5^n + 4^n + 3^n + 2^n.at n=20A057288
- a(n) = (n^(n+1) + n^(n-1))/2.at n=4A062023
- Positive numbers whose product of digits is 5 times their sum.at n=42A062382
- Heights of peaks of more than 8000 meters (as of Sep 25 2001), in decreasing order.at n=8A064296
- Numbers k such that the squarefree part of k equals A062799(k).at n=20A069551