665745 has 8 divisors (see below), whose sum is σ = 1065216. Its totient is φ = 355056.

The previous prime is 665723. The next prime is 665747. The reversal of 665745 is 547566.

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

It is not a de Polignac number, because 665745 - 2⁵ = 665713 is a prime.

665745 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (665747) 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 7 ways as a sum of consecutive naturals, for example, 22177 + ... + 22206.

It is an arithmetic number, because the mean of its divisors is an integer number (133152).

2⁶⁶⁵⁷⁴⁵ is an apocalyptic number.

It is an amenable number.

665745 is a deficient number, since it is larger than the sum of its proper divisors (399471).

665745 is a wasteful number, since it uses less digits than its factorization.

665745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44391.

The product of its digits is 25200, while the sum is 33.

The square root of 665745 is about 815.9319824593. The cubic root of 665745 is about 87.3177704076.

The spelling of 665745 in words is "six hundred sixty-five thousand, seven hundred forty-five".