666536635665 has 48 divisors (see below), whose sum is σ = 1174609158528. Its totient is φ = 349572630528.

The previous prime is 666536635649. The next prime is 666536635717. The reversal of 666536635665 is 566536635666.

666536635665 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 666536635665 - 2⁴ = 666536635649 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1548084 + ... + 1931226.

It is an arithmetic number, because the mean of its divisors is an integer number (24471024136).

Almost surely, 2^666536635665 is an apocalyptic number.

It is an amenable number.

666536635665 is a deficient number, since it is larger than the sum of its proper divisors (508072522863).

666536635665 is a wasteful number, since it uses less digits than its factorization.

666536635665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 383798 (or 383795 counting only the distinct ones).

The product of its digits is 314928000, while the sum is 63.

Subtracting from 666536635665 its reverse (566536635666), we obtain a palindrome (99999999999).

The spelling of 666536635665 in words is "six hundred sixty-six billion, five hundred thirty-six million, six hundred thirty-five thousand, six hundred sixty-five".