665638588737 has 12 divisors (see below), whose sum is σ = 961486284564. Its totient is φ = 443755217760.

The previous prime is 665638588723. The next prime is 665638588753. The reversal of 665638588737 is 737885836566.

665638588737 is a `hidden beast` number, since 6 + 6 + 5 + 6 + 3 + 8 + 588 + 7 + 37 = 666.

665638588737 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 2 ways, for example, as 438189717681 + 227448871056 = 661959^2 + 476916^2 .

It is not a de Polignac number, because 665638588737 - 2¹² = 665638584641 is a prime.

It is not an unprimeable number, because it can be changed into a prime (665638588757) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1116787 + ... + 1605767.

It is an arithmetic number, because the mean of its divisors is an integer number (80123857047).

Almost surely, 2^665638588737 is an apocalyptic number.

It is an amenable number.

665638588737 is a deficient number, since it is larger than the sum of its proper divisors (295847695827).

665638588737 is a wasteful number, since it uses less digits than its factorization.

665638588737 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 640240 (or 640237 counting only the distinct ones).

The product of its digits is 1219276800, while the sum is 72.

The spelling of 665638588737 in words is "six hundred sixty-five billion, six hundred thirty-eight million, five hundred eighty-eight thousand, seven hundred thirty-seven".