15551
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- yes
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 15552
- 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
- 15550
- Möbius Function
- -1
- Radical
- 15551
- 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
- 146
- 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
- 1814
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Palindromic primes: prime numbers whose decimal expansion is a palindrome.at n=34A002385
- Class 1+ primes: primes of the form 2^i*3^j - 1 with i, j >= 0.at n=27A005105
- Strobogrammatic primes: the same upside down (calculator-style numerals).at n=11A018847
- Primes that contain digits 1 and 5 only.at n=7A020453
- Greater of two consecutive palindromes, both of which are prime.at n=9A032594
- Palindromic prime lengths of factorials: see A035067.at n=18A035068
- Palindromic primes containing at least one pair of consecutive equal digits.at n=4A050786
- Fourth term of strong prime quintets: p(m-2)-p(m-3) > p(m-1)-p(m-2) > p(m)-p(m-1) > p(m+1)-p(m).at n=35A054811
- Palindromic primes using only two distinct digits and only the exterior digit is different.at n=16A056728
- Palindromic primes with just two distinct digits.at n=18A056730
- a(n) = 48*n^2 - 1.at n=18A065532
- Primes which can be expressed as concatenation of powers of 5 and 0's.at n=21A066596
- Primes in which a string of 5's is sandwiched between two 1's.at n=2A068646
- Primes which are a sandwich of numbers using at most one digit between two 1's.at n=7A068685
- Numbers n such that phi(n) + sigma(n) = n + reversal(n).at n=35A069217
- Primes of the form sum 6d/(2 + mu(d)) for some k and all d dividing k.at n=29A069548
- Primes with either no internal digits or all internal digits are 5.at n=52A069680
- Primes p such that x^5 = 2 has a solution mod p, but x^(5^2) = 2 has no solution mod p.at n=11A070182
- Palindromic primes with prime middle digit.at n=18A076611
- Palindromic primes with middle digit 5.at n=5A082441