665443 has 4 divisors (see below), whose sum is σ = 667480. Its totient is φ = 663408.

The previous prime is 665429. The next prime is 665447. The reversal of 665443 is 344566.

665443 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 344566 = 2 ⋅172283.

It is a cyclic number.

It is not a de Polignac number, because 665443 - 2¹⁷ = 534371 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (665447) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 405 + ... + 1222.

It is an arithmetic number, because the mean of its divisors is an integer number (166870).

2⁶⁶⁵⁴⁴³ is an apocalyptic number.

665443 is a deficient number, since it is larger than the sum of its proper divisors (2037).

665443 is a wasteful number, since it uses less digits than its factorization.

665443 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2036.

The product of its digits is 8640, while the sum is 28.

The square root of 665443 is about 815.7468970214. The cubic root of 665443 is about 87.3045651739.

The spelling of 665443 in words is "six hundred sixty-five thousand, four hundred forty-three".