665888 has 12 divisors (see below), whose sum is σ = 1311030. Its totient is φ = 332928.

The previous prime is 665857. The next prime is 665897. The reversal of 665888 is 888566.

It can be written as a sum of positive squares in only one way, i.e., 620944 + 44944 = 788^2 + 212^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10373 + ... + 10436.

2⁶⁶⁵⁸⁸⁸ is an apocalyptic number.

It is an amenable number.

665888 is a deficient number, since it is larger than the sum of its proper divisors (645142).

665888 is a wasteful number, since it uses less digits than its factorization.

665888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20819 (or 20811 counting only the distinct ones).

The product of its digits is 92160, while the sum is 41.

The square root of 665888 is about 816.0196076076. The cubic root of 665888 is about 87.3240218238.

The spelling of 665888 in words is "six hundred sixty-five thousand, eight hundred eighty-eight".