665605648 has 80 divisors (see below), whose sum is σ = 1383840000. Its totient is φ = 309450240.

The previous prime is 665605639. The next prime is 665605693. The reversal of 665605648 is 846506566.

It is a Harshad number since it is a multiple of its sum of digits (46).

It is a junction number, because it is equal to n+sod(n) for n = 665605598 and 665605607.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3344653 + ... + 3344851.

It is an arithmetic number, because the mean of its divisors is an integer number (17298000).

Almost surely, 2^665605648 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665605648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (691920000).

665605648 is an abundant number, since it is smaller than the sum of its proper divisors (718234352).

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

665605648 is a wasteful number, since it uses less digits than its factorization.

665605648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 440 (or 434 counting only the distinct ones).

The product of its (nonzero) digits is 1036800, while the sum is 46.

The square root of 665605648 is about 25799.3342549764. The cubic root of 665605648 is about 873.1167760681.

The spelling of 665605648 in words is "six hundred sixty-five million, six hundred five thousand, six hundred forty-eight".