665873 has 16 divisors (see below), whose sum is σ = 798336. Its totient is φ = 549120.

The previous prime is 665857. The next prime is 665897. The reversal of 665873 is 378566.

It is a happy number.

It is not a de Polignac number, because 665873 - 2⁴ = 665857 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 (665803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5018 + ... + 5148.

It is an arithmetic number, because the mean of its divisors is an integer number (49896).

2⁶⁶⁵⁸⁷³ is an apocalyptic number.

It is an amenable number.

665873 is a deficient number, since it is larger than the sum of its proper divisors (132463).

665873 is a wasteful number, since it uses less digits than its factorization.

665873 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 184.

The product of its digits is 30240, while the sum is 35.

The square root of 665873 is about 816.0104166002. The cubic root of 665873 is about 87.3233661229.

The spelling of 665873 in words is "six hundred sixty-five thousand, eight hundred seventy-three".