665218340 has 48 divisors (see below), whose sum is σ = 1420617072. Its totient is φ = 261605376.

The previous prime is 665218339. The next prime is 665218349. The reversal of 665218340 is 43812566.

665218340 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 86527204 + 578691136 = 9302^2 + 24056^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 665218340.

It is not an unprimeable number, because it can be changed into a prime (665218349) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 666722 + ... + 667718.

It is an arithmetic number, because the mean of its divisors is an integer number (29596189).

Almost surely, 2^665218340 is an apocalyptic number.

It is an amenable number.

665218340 is an abundant number, since it is smaller than the sum of its proper divisors (755398732).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

665218340 is a wasteful number, since it uses less digits than its factorization.

665218340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1536 (or 1534 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 35.

The square root of 665218340 is about 25791.8270000401. The cubic root of 665218340 is about 872.9473911248.

The spelling of 665218340 in words is "six hundred sixty-five million, two hundred eighteen thousand, three hundred forty".