7777
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 28
- Digital Root
- 1
- Palindromic Number
- yes
- Repdigit
- yes
- Automorphic
- no
- Kaprekar Number
- yes
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 9792
- Proper Divisor Sum (Aliquot Sum)
- 2015
- 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
- 6000
- Möbius Function
- -1
- Radical
- 7777
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 3
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
- 83
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- Deceptive nonprimes: composite numbers k that divide the repunit R_{k-1}.at n=16A000864
- Numbers k such that 21*2^k - 1 is prime.at n=23A002238
- a(n) = 7*(10^n - 1)/9.at n=4A002281
- a(n) = n^5 + 1.at n=7A002561
- Logarithmic numbers.at n=6A002747
- Smallest number containing n syllables in UK English.at n=13A002810
- Numbers that are the sum of 2 positive 5th powers.at n=15A003347
- Numbers that are the sum of at most 2 positive 5th powers.at n=22A004842
- Pseudoprimes to base 10.at n=27A005939
- Kaprekar numbers: positive numbers n such that n = q+r and n^2 = q*10^m+r, for some m >= 1, q >= 0 and 0 <= r < 10^m, with n != 10^a, a >= 1.at n=15A006886
- Repdigit numbers, or numbers whose digits are all equal.at n=34A010785
- Numbers > 9 with all digits the same.at n=24A014181
- Pseudoprimes to base 100.at n=42A020228
- Positive numbers k such that k = x^5 + y^5 has a solution in nonzero integers x, y.at n=30A020896
- Palindromic in bases 6 and 10.at n=17A029963
- Numbers k such that k^2 is palindromic in base 6.at n=17A029990
- Sums of distinct powers of 6.at n=33A033043
- Numbers whose maximal base-10 run length is 4.at n=6A033285
- Positive numbers having the same set of digits in base 2 and base 6.at n=29A037411
- Sums of 2 distinct powers of 6.at n=10A038478