665957 has 4 divisors (see below), whose sum is σ = 670956. Its totient is φ = 660960.

The previous prime is 665953. The next prime is 665981. The reversal of 665957 is 759566.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 516961 + 148996 = 719^2 + 386^2 .

It is a cyclic number.

It is not a de Polignac number, because 665957 - 2² = 665953 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 665957.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665953) 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, 2294 + ... + 2567.

It is an arithmetic number, because the mean of its divisors is an integer number (167739).

2⁶⁶⁵⁹⁵⁷ is an apocalyptic number.

It is an amenable number.

665957 is a deficient number, since it is larger than the sum of its proper divisors (4999).

665957 is a wasteful number, since it uses less digits than its factorization.

665957 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4998.

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

The square root of 665957 is about 816.0618849082. The cubic root of 665957 is about 87.3270379213.

The spelling of 665957 in words is "six hundred sixty-five thousand, nine hundred fifty-seven".