665663 has 8 divisors (see below), whose sum is σ = 696960. Its totient is φ = 635040.

The previous prime is 665659. The next prime is 665677. The reversal of 665663 is 366566.

665663 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 665663 - 2² = 665659 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665603) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3281 + ... + 3477.

It is an arithmetic number, because the mean of its divisors is an integer number (87120).

2⁶⁶⁵⁶⁶³ is an apocalyptic number.

665663 is a deficient number, since it is larger than the sum of its proper divisors (31297).

665663 is a wasteful number, since it uses less digits than its factorization.

665663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 337.

The product of its digits is 19440, while the sum is 32.

The square root of 665663 is about 815.8817316254. The cubic root of 665663 is about 87.3141852756.

The spelling of 665663 in words is "six hundred sixty-five thousand, six hundred sixty-three".