665711 has 4 divisors (see below), whose sum is σ = 672672. Its totient is φ = 658752.

The previous prime is 665677. The next prime is 665713. The reversal of 665711 is 117566.

665711 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 665711 - 2¹⁰ = 664687 is a prime.

It is a super-2 number, since 2×665711² = 886342271042, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 665711.

It is not an unprimeable number, because it can be changed into a prime (665713) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3335 + ... + 3528.

It is an arithmetic number, because the mean of its divisors is an integer number (168168).

2⁶⁶⁵⁷¹¹ is an apocalyptic number.

665711 is a deficient number, since it is larger than the sum of its proper divisors (6961).

665711 is an equidigital number, since it uses as much as digits as its factorization.

665711 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6960.

The product of its digits is 1260, while the sum is 26.

The square root of 665711 is about 815.9111471233. The cubic root of 665711 is about 87.3162839252.

The spelling of 665711 in words is "six hundred sixty-five thousand, seven hundred eleven".