665613648 has 360 divisors, whose sum is σ = 2381633280. Its totient is φ = 172247040.

The previous prime is 665613647. The next prime is 665613653. The reversal of 665613648 is 846316566.

665613648 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665613647) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 3718423 + ... + 3718601.

It is an arithmetic number, because the mean of its divisors is an integer number (6615648).

Almost surely, 2^665613648 is an apocalyptic number.

665613648 is a gapful number since it is divisible by the number (68) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665613648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1190816640).

665613648 is an abundant number, since it is smaller than the sum of its proper divisors (1716019632).

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

665613648 is a wasteful number, since it uses less digits than its factorization.

665613648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 255 (or 239 counting only the distinct ones).

The product of its digits is 622080, while the sum is 45.

The square root of 665613648 is about 25799.4892972710. The cubic root of 665613648 is about 873.1202740884.

The spelling of 665613648 in words is "six hundred sixty-five million, six hundred thirteen thousand, six hundred forty-eight".