665759 has 4 divisors (see below), whose sum is σ = 670320. Its totient is φ = 661200.

The previous prime is 665747. The next prime is 665761. The reversal of 665759 is 957566.

665759 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.

It is a cyclic number.

It is not a de Polignac number, because 665759 - 2⁸ = 665503 is a prime.

It is an Ulam number.

It is a Duffinian number.

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 3 ways as a sum of consecutive naturals, for example, 2054 + ... + 2355.

It is an arithmetic number, because the mean of its divisors is an integer number (167580).

2⁶⁶⁵⁷⁵⁹ is an apocalyptic number.

665759 is a deficient number, since it is larger than the sum of its proper divisors (4561).

665759 is a wasteful number, since it uses less digits than its factorization.

665759 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4560.

The product of its digits is 56700, while the sum is 38.

The square root of 665759 is about 815.9405615607. The cubic root of 665759 is about 87.3183824739.

The spelling of 665759 in words is "six hundred sixty-five thousand, seven hundred fifty-nine".