51

domain: N

Properties

Digital Properties

Digit Count
2
Digit Sum
6
Digital Root
6
Palindromic Number
no
Repdigit
no
Automorphic
no
Kaprekar Number
no
Multiplicative Persistence
1

Divisibility

Divisor Count
4
Divisor Sum
72
Proper Divisor Sum (Aliquot Sum)
21
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
32
Möbius Function
1
Radical
51
Omega Function (Ω)
2
Little Omega Function (ω)
2

Special

Factorial
no
Catalan Number
no
Bell Number
no
Motzkin Number
yes
Primorial
no

Figurate Numbers

Fibonacci Number
no
Triangular Number
no
Perfect Square
no
Perfect Cube
no
Pentagonal Number
yes
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
24
Smith Number
no

Classification

Natural
yes
Even
no
Odd
yes

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

Names

German
einundfünfzig· ordinal: einundfünfzigste
English
fifty-one· ordinal: fifty-first
Spanish
cincuenta y uno· ordinal: 51º
French
cinquante et un· ordinal: cinquante et unième
Italian
cinquantuno· ordinal: 51º
Latin
quinquaginta unus· ordinal: 51.
Portuguese
cinquenta e um· ordinal: 51º

Appears in sequences