345
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 576
- Proper Divisor Sum (Aliquot Sum)
- 231
- 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
- 176
- Möbius Function
- -1
- Radical
- 345
- 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
- 125
- Smith 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
Names
- German
- dreihundertfünfundvierzig· ordinal: dreihundertfünfundvierzigste
- English
- three hundred forty-five· ordinal: three hundred forty-fifth
- Spanish
- trescientos cuarenta y cinco· ordinal: 345º
- French
- trois cent quarante-cinq· ordinal: trois cent quarante-cinqième
- Italian
- trecentoquarantacinque· ordinal: 345º
- Latin
- trecenti quadraginta quinque· ordinal: 345.
- Portuguese
- trezentos e quarenta e cinco· ordinal: 345º
Appears in sequences
- Number of partitions of n if there are two kinds of 1, two kinds of 2 and two kinds of 3.at n=10A000098
- Triangle of numbers related to triangle A049213; generalization of Stirling numbers of second kind A008277, Bessel triangle A001497.at n=12A000369
- Number of n-node unrooted steric quartic trees; number of n-carbon alkanes C(n)H(2n+2) taking stereoisomers into account.at n=11A000628
- Boustrophedon transform of primes.at n=5A000747
- Euler's "numerus idoneus" (or "numeri idonei", or idoneal, or suitable, or convenient numbers).at n=54A000926
- a(n) is the solution to the postage stamp problem with 5 denominations and n stamps.at n=6A001210
- Numbers that are the sum of 4 cubes in more than 1 way.at n=17A001245
- Generalized pentagonal numbers: m*(3*m - 1)/2, m = 0, +-1, +-2, +-3, ....at n=30A001318
- Number of graphs with n nodes and n-1 edges.at n=8A001433
- Decimal concatenation of n, n+1, and n+2.at n=3A001703
- Expansion of g.f. x/((1 - x)^2*(1 - x^3)).at n=44A001840
- Denominators of cosecant numbers: -2*(2^(2*n-1)-1)*Bernoulli(2*n).at n=22A001897
- Numbers dividing A002037(i) and larger than A002037(i-1), for some i>0.at n=30A002038
- Number of pairs of consecutive integers x, x+1 such that all prime factors of both x and x+1 are at most the n-th prime.at n=9A002071
- Number of partitions of n into nonprime parts.at n=32A002095
- a(1) = 0, a(2) = -2; for n > 2, a(n) + a(n-2) - a(n-3) - a(n-5) - ... - a(n-p) = (-1)^(n+1)*n if n is prime, otherwise = 0, where p = largest prime < n.at n=27A002120
- Odd squarefree numbers with an odd number of prime factors that have no prime factors greater than 31.at n=17A002556
- Numbers k such that (k^2 + k + 1)/7 is prime.at n=35A002641
- Numbers k such that (k^2 + 1)/2 is prime.at n=54A002731
- Self numbers or Colombian numbers (numbers that are not of the form m + sum of digits of m for any m).at n=37A003052