665968 has 20 divisors (see below), whose sum is σ = 1305720. Its totient is φ = 329024.

The previous prime is 665953. The next prime is 665981. The reversal of 665968 is 869566.

It is a self number, because there is not a number n which added to its sum of digits gives 665968.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1518 + ... + 1906.

It is an arithmetic number, because the mean of its divisors is an integer number (65286).

2⁶⁶⁵⁹⁶⁸ is an apocalyptic number.

It is an amenable number.

665968 is a deficient number, since it is larger than the sum of its proper divisors (639752).

665968 is a wasteful number, since it uses less digits than its factorization.

665968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 504 (or 498 counting only the distinct ones).

The product of its digits is 77760, while the sum is 40.

The square root of 665968 is about 816.0686245654. The cubic root of 665968 is about 87.3275187292.

The spelling of 665968 in words is "six hundred sixty-five thousand, nine hundred sixty-eight".