665655 has 16 divisors (see below), whose sum is σ = 1075200. Its totient is φ = 351648.

The previous prime is 665633. The next prime is 665659. The reversal of 665655 is 556566.

It is not a de Polignac number, because 665655 - 2⁶ = 665591 is a prime.

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 polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2874 + ... + 3096.

It is an arithmetic number, because the mean of its divisors is an integer number (67200).

2⁶⁶⁵⁶⁵⁵ is an apocalyptic number.

665655 is a deficient number, since it is larger than the sum of its proper divisors (409545).

665655 is a wasteful number, since it uses less digits than its factorization.

665655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 430.

The product of its digits is 27000, while the sum is 33.

The square root of 665655 is about 815.8768289393. The cubic root of 665655 is about 87.3138354909.

Adding to 665655 its reverse (556566), we get a palindrome (1222221).

The spelling of 665655 in words is "six hundred sixty-five thousand, six hundred fifty-five".