665726544 has 90 divisors (see below), whose sum is σ = 2167313850. Its totient is φ = 190205568.

The previous prime is 665726543. The next prime is 665726569. The reversal of 665726544 is 445627566.

665726544 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 only one way, i.e., 665020944 + 705600 = 25788^2 + 840^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 665726544.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665726543) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 40119 + ... + 54230.

It is an arithmetic number, because the mean of its divisors is an integer number (24081265).

Almost surely, 2^665726544 is an apocalyptic number.

It is an amenable number.

665726544 is an abundant number, since it is smaller than the sum of its proper divisors (1501587306).

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

665726544 is a wasteful number, since it uses less digits than its factorization.

665726544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94377 (or 94361 counting only the distinct ones).

The product of its digits is 1209600, while the sum is 45.

The square root of 665726544 is about 25801.6771547898. The cubic root of 665726544 is about 873.1696351626.

The spelling of 665726544 in words is "six hundred sixty-five million, seven hundred twenty-six thousand, five hundred forty-four".