665656 has 8 divisors (see below), whose sum is σ = 1248120. Its totient is φ = 332824.

The previous prime is 665633. The next prime is 665659. The reversal of 665656 is 656566.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41596 + ... + 41611.

It is an arithmetic number, because the mean of its divisors is an integer number (156015).

2⁶⁶⁵⁶⁵⁶ is an apocalyptic number.

It is an amenable number.

665656 is a deficient number, since it is larger than the sum of its proper divisors (582464).

665656 is a wasteful number, since it uses less digits than its factorization.

665656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83213 (or 83209 counting only the distinct ones).

The product of its digits is 32400, while the sum is 34.

The square root of 665656 is about 815.8774417766. The cubic root of 665656 is about 87.3138792141.

The spelling of 665656 in words is "six hundred sixty-five thousand, six hundred fifty-six".