761
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 762
- Proper Divisor Sum (Aliquot Sum)
- 1
- 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
- 760
- Möbius Function
- -1
- Radical
- 761
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 33
- Smith 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
- yes
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 135
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Names
- German
- siebenhunderteinundsechzig· ordinal: siebenhunderteinundsechzigste
- English
- seven hundred sixty-one· ordinal: seven hundred sixty-first
- Spanish
- setecientos sesenta y uno· ordinal: 761º
- French
- sept cent soixante et un· ordinal: sept cent soixante et unième
- Italian
- settecentosessantuno· ordinal: 761º
- Latin
- septingenti sexaginta unus· ordinal: 761.
- Portuguese
- setecentos e sessenta e um· ordinal: 761º
Appears in sequences
- a(n) = Sum_{k = 1..n} floor(2^k / k).at n=11A000801
- Irregular primes: primes p such that at least one of the numerators of the Bernoulli numbers B_2, B_4, ..., B_{p-3} (A000367) is divisible by p.at n=50A000928
- a(n) = ceiling(n^2/2).at n=39A000982
- a(n) = numerator of harmonic number H(n) = Sum_{i=1..n} 1/i.at n=7A001008
- Primes with 6 as smallest primitive root.at n=8A001125
- Centered square numbers: a(n) = 2*n*(n+1)+1. Sums of two consecutive squares. Also, consider all Pythagorean triples (X, Y, Z=Y+1) ordered by increasing Z; then sequence gives Z values.at n=19A001844
- Cyclic numbers: 10 is a quadratic residue modulo p and class of mantissa is 2.at n=42A001914
- Numerator of the n-th harmonic number H(n) divided by (n+1); a(n) = A001008(n) / ((n+1)*A002805(n)).at n=7A002547
- Numbers that are the sum of 4 positive 5th powers.at n=13A003349
- Primes of the form 2^a + 3^b.at n=30A004051
- Primes written backwards.at n=38A004087
- Divisible only by primes congruent to 1 mod 5.at n=37A004615
- Divisible only by primes congruent to 5 mod 7.at n=36A004623
- Numbers divisible only by primes congruent to 1 mod 8.at n=31A004625
- Numbers that are the sum of at most 4 positive 5th powers.at n=33A004844
- Numbers that are the sum of at most 5 positive 5th powers.at n=49A004845
- a(n) = ceiling(n*phi^9), where phi is the golden ratio, A001622.at n=10A004964
- Sophie Germain primes p: 2p+1 is also prime.at n=33A005384
- Primitive prime factors of the sequence k^2 + 1 (A002522) in the order that they are found.at n=27A005529
- Number of certain self-avoiding walks with n steps on square lattice (see reference for precise definition).at n=14A006142