It is a strong prime.
It is a cyclic number.
It is a Sophie Germain prime.
It is a Chen prime.
It is the 17-th Jacobsthal number.
It is a plaindrome in base 4 and base 16.
43691 is a Friedman number, since it can be written as (4^9+3-1)/6, using all its digits and the basic arithmetic operations.
243691 is an apocalyptic number.
43691 is an equidigital number, since it uses as much as digits as its factorization.
43691 is an odious number, because the sum of its binary digits is odd.
The square root of 43691 is about 209.0239220759. The cubic root of 43691 is about 35.2206468918.
The spelling of 43691 in words is "forty-three thousand, six hundred ninety-one".