665568 has 36 divisors (see below), whose sum is σ = 1893528. Its totient is φ = 221760.

The previous prime is 665563. The next prime is 665569. The reversal of 665568 is 865566.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665563) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 868 + ... + 1443.

It is an arithmetic number, because the mean of its divisors is an integer number (52598).

2⁶⁶⁵⁵⁶⁸ is an apocalyptic number.

It is an amenable number.

665568 is an abundant number, since it is smaller than the sum of its proper divisors (1227960).

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

665568 is a wasteful number, since it uses less digits than its factorization.

665568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2327 (or 2316 counting only the distinct ones).

The product of its digits is 43200, while the sum is 36.

The square root of 665568 is about 815.8235103256. The cubic root of 665568 is about 87.3100314008.

It can be divided in two parts, 66556 and 8, that added together give a square (66564 = 258²).

The spelling of 665568 in words is "six hundred sixty-five thousand, five hundred sixty-eight".