643261564102056 has 64 divisors (see below), whose sum is σ = 1609823078853120. Its totient is φ = 214197993831360.

The previous prime is 643261564102051. The next prime is 643261564102057. The reversal of 643261564102056 is 650201465162346.

It is not an unprimeable number, because it can be changed into a prime (643261564102051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 366399471 + ... + 368150913.

It is an arithmetic number, because the mean of its divisors is an integer number (25153485607080).

Almost surely, 2^{643261564102056} is an apocalyptic number.

It is an amenable number.

643261564102056 is an abundant number, since it is smaller than the sum of its proper divisors (966561514751064).

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

643261564102056 is a wasteful number, since it uses less digits than its factorization.

643261564102056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1767326 (or 1767322 counting only the distinct ones).

The product of its (nonzero) digits is 6220800, while the sum is 51.

The spelling of 643261564102056 in words is "six hundred forty-three trillion, two hundred sixty-one billion, five hundred sixty-four million, one hundred two thousand, fifty-six".