305665 has 8 divisors (see below), whose sum is σ = 370728. Its totient is φ = 241920.

The previous prime is 305663. The next prime is 305717. The reversal of 305665 is 566503.

It can be written as a sum of positive squares in 4 ways, for example, as 961 + 304704 = 31^2 + 552^2 .

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

It is not a de Polignac number, because 305665 - 2¹ = 305663 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (305663) 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, 295 + ... + 835.

It is an arithmetic number, because the mean of its divisors is an integer number (46341).

2³⁰⁵⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

305665 is a deficient number, since it is larger than the sum of its proper divisors (65063).

305665 is a wasteful number, since it uses less digits than its factorization.

305665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 659.

The product of its (nonzero) digits is 2700, while the sum is 25.

The square root of 305665 is about 552.8697857543. The cubic root of 305665 is about 67.3620410432.

The spelling of 305665 in words is "three hundred five thousand, six hundred sixty-five".