15253
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 17440
- Proper Divisor Sum (Aliquot Sum)
- 2187
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 13068
- Möbius Function
- 1
- Radical
- 15253
- Omega Function (Ω)
- 2
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 32
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 70 ones.at n=25A031838
- Decimal part of cube root of a(n) starts with 8: first term of runs.at n=23A034134
- Generalized Pellian with 2nd term equal to 6.at n=10A048693
- Half the number of 5 X n binary arrays with a path of adjacent 1's and a path of adjacent 0's from top row to bottom row.at n=2A069398
- Half the number of n X 4 binary arrays with a path of adjacent 1's and a path of adjacent 0's from top row to bottom row.at n=4A069404
- Partition the concatenation 1234567...of natural numbers into successive strings which are multiples of 7, all different and > 7 (0 is never taken as the most significant digit).at n=12A077300
- a(n) = 9*n^2 + 3*n + 1.at n=41A082040
- Let S = 123456789101112131415..., the concatenation of the natural numbers; partition this string into distinct squarefree numbers. To avoid leading zeros, no number may end at the digit that comes before a 0 in S.at n=34A085943
- Eight bishops and one elephant on a 3 X 3 chessboard. a(n) = 2^(n+2) - 3*F(n+2).at n=12A175660
- Triangle read by rows: T(n,m)=A060187(1+n,1+m) *n! / (n-m)!at n=29A177429
- Numbers n such that the greatest prime divisor p of n^2+1 has the property that (p - n)^2 + 1 = p.at n=43A206246
- Least integer k such that the n-th prime of form m^2+1 divides the composite number k^2+1.at n=22A255675
- a(n) = 1 - sigma(n) + sigma(n)^2.at n=47A259184
- A self-"read and extend" sequence built following the rules visible in the Comments section (a kind of Collatz-by-digits sequence).at n=37A316764
- Number of separable partitions of n in which the number of distinct (repeatable) parts is > 4.at n=38A325719
- Number of integer partitions of n such that the maximum is greater than twice the median.at n=35A361857
- a(n) = Sum_{k=0..n} (-1)^k * binomial(n+k-1,k) * binomial(5*n-k-1,n-k).at n=5A370105
- Intersection of A002061 and A016105.at n=28A370519