665956 has 12 divisors (see below), whose sum is σ = 1205820. Its totient is φ = 321440.

The previous prime is 665953. The next prime is 665981. The reversal of 665956 is 659566.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 341056 + 324900 = 584^2 + 570^2 .

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, 2755 + ... + 2986.

It is an arithmetic number, because the mean of its divisors is an integer number (100485).

2⁶⁶⁵⁹⁵⁶ is an apocalyptic number.

It is an amenable number.

665956 is a deficient number, since it is larger than the sum of its proper divisors (539864).

665956 is a wasteful number, since it uses less digits than its factorization.

665956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5774 (or 5772 counting only the distinct ones).

The product of its digits is 48600, while the sum is 37.

The square root of 665956 is about 816.0612722094. The cubic root of 665956 is about 87.3269942113.

The spelling of 665956 in words is "six hundred sixty-five thousand, nine hundred fifty-six".