646643052405664 has 24 divisors (see below), whose sum is σ = 1340082641499840. Its totient is φ = 306304603770816.

The previous prime is 646643052405643. The next prime is 646643052405667. The reversal of 646643052405664 is 466504250346646.

It is not an unprimeable number, because it can be changed into a prime (646643052405667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 531778825384 + ... + 531778826599.

It is an arithmetic number, because the mean of its divisors is an integer number (55836776729160).

Almost surely, 2^{646643052405664} is an apocalyptic number.

It is an amenable number.

646643052405664 is an abundant number, since it is smaller than the sum of its proper divisors (693439589094176).

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

646643052405664 is a wasteful number, since it uses less digits than its factorization.

646643052405664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1063557652012 (or 1063557652004 counting only the distinct ones).

The product of its (nonzero) digits is 298598400, while the sum is 61.

The spelling of 646643052405664 in words is "six hundred forty-six trillion, six hundred forty-three billion, fifty-two million, four hundred five thousand, six hundred sixty-four".