665843 has 2 divisors, whose sum is σ = 665844. Its totient is φ = 665842.

The previous prime is 665813. The next prime is 665857. The reversal of 665843 is 348566.

665843 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 665843 - 2¹⁶ = 600307 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (665803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332921 + 332922.

It is an arithmetic number, because the mean of its divisors is an integer number (332922).

2⁶⁶⁵⁸⁴³ is an apocalyptic number.

665843 is a deficient number, since it is larger than the sum of its proper divisors (1).

665843 is an equidigital number, since it uses as much as digits as its factorization.

665843 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17280, while the sum is 32.

The square root of 665843 is about 815.9920342748. The cubic root of 665843 is about 87.3220546915.

The spelling of 665843 in words is "six hundred sixty-five thousand, eight hundred forty-three".