665449 has 4 divisors (see below), whose sum is σ = 676420. Its totient is φ = 654480.

The previous prime is 665447. The next prime is 665479. The reversal of 665449 is 944566.

665449 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 can be written as a sum of positive squares in 2 ways, for example, as 75625 + 589824 = 275^2 + 768^2 .

It is a cyclic number.

It is not a de Polignac number, because 665449 - 2¹ = 665447 is a prime.

It is a Duffinian number.

665449 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (665447) 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, 5394 + ... + 5515.

It is an arithmetic number, because the mean of its divisors is an integer number (169105).

2⁶⁶⁵⁴⁴⁹ is an apocalyptic number.

It is an amenable number.

665449 is a deficient number, since it is larger than the sum of its proper divisors (10971).

665449 is a wasteful number, since it uses less digits than its factorization.

665449 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10970.

The product of its digits is 25920, while the sum is 34.

The square root of 665449 is about 815.7505746244. The cubic root of 665449 is about 87.3048275684.

The spelling of 665449 in words is "six hundred sixty-five thousand, four hundred forty-nine".