665907648 has 168 divisors, whose sum is σ = 2106027792. Its totient is φ = 185020416.

The previous prime is 665907637. The next prime is 665907653. The reversal of 665907648 is 846709566.

It is a tau number, because it is divible by the number of its divisors (168).

It is a self number, because there is not a number n which added to its sum of digits gives 665907648.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 347140 + ... + 349052.

Almost surely, 2^665907648 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 665907648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1053013896).

665907648 is an abundant number, since it is smaller than the sum of its proper divisors (1440120144).

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

665907648 is a wasteful number, since it uses less digits than its factorization.

665907648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1979 (or 1962 counting only the distinct ones).

The product of its (nonzero) digits is 2177280, while the sum is 51.

The square root of 665907648 is about 25805.1864554395. The cubic root of 665907648 is about 873.2488068974.

The spelling of 665907648 in words is "six hundred sixty-five million, nine hundred seven thousand, six hundred forty-eight".