665943 has 8 divisors (see below), whose sum is σ = 907008. Its totient is φ = 434424.

The previous prime is 665923. The next prime is 665947. The reversal of 665943 is 349566.

It is a happy number.

665943 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 665943 - 2¹⁴ = 649559 is a prime.

It is a plaindrome in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665947) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2221 + ... + 2502.

It is an arithmetic number, because the mean of its divisors is an integer number (113376).

2⁶⁶⁵⁹⁴³ is an apocalyptic number.

665943 is a deficient number, since it is larger than the sum of its proper divisors (241065).

665943 is a wasteful number, since it uses less digits than its factorization.

665943 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4773.

The product of its digits is 19440, while the sum is 33.

The square root of 665943 is about 816.0533070823. The cubic root of 665943 is about 87.3264259764.

The spelling of 665943 in words is "six hundred sixty-five thousand, nine hundred forty-three".