15889
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 31
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 15890
- 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
- 15888
- Möbius Function
- -1
- Radical
- 15889
- 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
- 53
- 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
- yes
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 1852
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Consider all ways of writing a number as p+2m^2 where p is 1 or a prime and m >= 0; sequence gives numbers that are expressible in at least 2 more ways than any smaller number.at n=14A016067
- Numbers k such that the continued fraction for sqrt(k) has period 37.at n=37A020376
- Number of partitions of n with equal number of parts congruent to each of 0, 1 and 3 (mod 4).at n=58A046767
- Smallest integer that can be expressed as p+2m^2 in more ways than any smaller number, where m >= 0 and p = 1 or prime.at n=35A055202
- Primes with 21 as smallest positive primitive root.at n=3A061333
- Primes for which the smallest positive primitive root is odd and nonprime.at n=8A070269
- Fixed points when A008475 is iterated started at factorials of prime numbers.at n=20A082085
- Upper twin primes of upper twin prime index.at n=18A088463
- Lesser prime factor of semiprimes in A089542.at n=10A089543
- Balanced primes of order five.at n=34A096697
- Indices of primes in sequence defined by A(0) = 49, A(n) = 10*A(n-1) - 51 for n > 0.at n=17A101725
- Primes with digit sum = 31.at n=17A106767
- Primes p = prime(i) of level (1,3), i.e., such that A118534(i) = prime(i-3).at n=25A118467
- Primes of the form k^2 + 13.at n=24A138375
- Primes congruent to 42 mod 53.at n=33A142572
- Primes congruent to 18 mod 59.at n=36A142745
- Primes congruent to 29 mod 61.at n=37A142827
- Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0) and consisting of n steps taken from {(-1, -1), (-1, 1), (-1, 0), (0, 1), (1, -1)}.at n=10A151260
- Primes in A154935.at n=39A154936
- Number of lines through at least 2 points of an 8 X n grid of points.at n=33A160848