665013520 has 20 divisors (see below), whose sum is σ = 1546156620. Its totient is φ = 266005376.

The previous prime is 665013511. The next prime is 665013527. The reversal of 665013520 is 25310566.

It can be written as a sum of positive squares in 2 ways, for example, as 196897024 + 468116496 = 14032^2 + 21636^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is not an unprimeable number, because it can be changed into a prime (665013527) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 4156255 + ... + 4156414.

It is an arithmetic number, because the mean of its divisors is an integer number (77307831).

Almost surely, 2^665013520 is an apocalyptic number.

It is an amenable number.

665013520 is an abundant number, since it is smaller than the sum of its proper divisors (881143100).

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

665013520 is a wasteful number, since it uses less digits than its factorization.

665013520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8312682 (or 8312676 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 28.

The square root of 665013520 is about 25787.8560566791. The cubic root of 665013520 is about 872.8577887453.

The spelling of 665013520 in words is "six hundred sixty-five million, thirteen thousand, five hundred twenty".