646689727986646 has 16 divisors (see below), whose sum is σ = 984520840882176. Its totient is φ = 318516193973736.

The previous prime is 646689727986611. The next prime is 646689727986671.

646689727986646 is nontrivially palindromic in base 10.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3547446 + ... + 36138121.

It is an arithmetic number, because the mean of its divisors is an integer number (61532552555136).

Almost surely, 2^{646689727986646} is an apocalyptic number.

646689727986646 is a deficient number, since it is larger than the sum of its proper divisors (337831112895530).

646689727986646 is a wasteful number, since it uses less digits than its factorization.

646689727986646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39807243.

The product of its digits is 379243855872, while the sum is 94.

The spelling of 646689727986646 in words is "six hundred forty-six trillion, six hundred eighty-nine billion, seven hundred twenty-seven million, nine hundred eighty-six thousand, six hundred forty-six".