665799 has 8 divisors (see below), whose sum is σ = 909552. Its totient is φ = 432960.

The previous prime is 665789. The next prime is 665801. The reversal of 665799 is 997566.

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

It is not a de Polignac number, because 665799 - 2⁴ = 665783 is a prime.

665799 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 665799.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665719) 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, 2584 + ... + 2829.

It is an arithmetic number, because the mean of its divisors is an integer number (113694).

2⁶⁶⁵⁷⁹⁹ is an apocalyptic number.

665799 is a deficient number, since it is larger than the sum of its proper divisors (243753).

665799 is a wasteful number, since it uses less digits than its factorization.

665799 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5457.

The product of its digits is 102060, while the sum is 42.

The square root of 665799 is about 815.9650727819. The cubic root of 665799 is about 87.3201311875.

The spelling of 665799 in words is "six hundred sixty-five thousand, seven hundred ninety-nine".