665588 has 24 divisors (see below), whose sum is σ = 1452864. Its totient is φ = 259200.

The previous prime is 665573. The next prime is 665591. The reversal of 665588 is 885566.

It is an Ulam number.

It is a zygodrome in base 10.

It is a congruent number.

It is an unprimeable number.

665588 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 773 + ... + 1388.

It is an arithmetic number, because the mean of its divisors is an integer number (60536).

2⁶⁶⁵⁵⁸⁸ is an apocalyptic number.

It is an amenable number.

665588 is an abundant number, since it is smaller than the sum of its proper divisors (787276).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

665588 is a wasteful number, since it uses less digits than its factorization.

665588 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2183 (or 2181 counting only the distinct ones).

The product of its digits is 57600, while the sum is 38.

The square root of 665588 is about 815.8357677866. The cubic root of 665588 is about 87.3109059336.

It can be divided in two parts, 66558 and 8, that added together give a palindrome (66566).

The spelling of 665588 in words is "six hundred sixty-five thousand, five hundred eighty-eight".