15061
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 15062
- Proper Divisor Sum (Aliquot Sum)
- 1
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 15060
- Möbius Function
- -1
- Radical
- 15061
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
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
- 133
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 1759
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- a(1) = 1; a(2) = 2; a(n) == a(k) (mod n-k) for all 1 < k < n.at n=12A002987
- a(0) = 1, a(n) = 11*n^2 + 2 for n>0.at n=37A010003
- Numbers k such that the continued fraction for sqrt(k) has period 59.at n=21A020398
- a(n) = Sum_{i=0..floor(n/2)} A047080(n,i).at n=17A047082
- Numbers n such that [A070080(n), A070081(n), A070082(n)] is an acute integer triangle with integer area.at n=29A070146
- a(n) = Sum_{i=0..floor(n/2)} (-1)^(i+floor(n/2))*T(2i+e), where T(n) are tribonacci numbers (A000073) and e = (1/2)(1-(-1)^n).at n=18A075111
- Sum of even-indexed terms of tribonacci numbers.at n=9A113300
- Least prime P such that 3*p(n)*P*(3*p(n)*P+1)-1, 3*p(n)*P*(3*p(n)*P+1)+1,3*p(n)*P*(3*p(n)*P+3)-1,3*p(n)*P*(3*p(n)*P+3)+1 are all primes with p(i) = i-th prime.at n=10A137839
- Primes congruent to 21 mod 47.at n=40A142372
- Primes congruent to 18 mod 49.at n=38A142429
- Primes congruent to 9 mod 53.at n=37A142539
- Primes congruent to 16 mod 59.at n=28A142743
- Primes congruent to 55 mod 61.at n=30A142853
- Primes p such that continued fraction of (1 + sqrt(p))/2 has period 15: primes in A146338.at n=28A146360
- Diagonal sums of Riordan array A154948.at n=16A154949
- Prime numbers ending in the prime number 61.at n=37A167445
- Prime hypotenuses c with concatenation p = c//a//b a prime number.at n=39A174885
- T(n,k)=Number of (n+1)X(k+1) 0..4 arrays with every 2X2 subblock commuting with each of its horizontal and vertical 2X2 subblock neighbors.at n=17A186484
- T(n,k)=Number of (n+1)X(k+1) 0..4 arrays with every 2X2 subblock commuting with each of its horizontal and vertical 2X2 subblock neighbors.at n=18A186484
- T(n,m)=Number of (n+1)X4 0..m arrays with every 2X2 subblock commuting with each of its horizontal and vertical 2X2 subblock neighbors.at n=24A188058