643156531264 has 28 divisors (see below), whose sum is σ = 1374437877484. Its totient is φ = 296841475584.

The previous prime is 643156531253. The next prime is 643156531279. The reversal of 643156531264 is 462135651346.

643156531264 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 197306532864 + 445849998400 = 444192^2 + 667720^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 386511507 + ... + 386513170.

It is an arithmetic number, because the mean of its divisors is an integer number (49087067053).

Almost surely, 2^643156531264 is an apocalyptic number.

643156531264 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

643156531264 is an abundant number, since it is smaller than the sum of its proper divisors (731281346220).

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

643156531264 is a wasteful number, since it uses less digits than its factorization.

643156531264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 773024702 (or 773024692 counting only the distinct ones).

The product of its digits is 1555200, while the sum is 46.

The spelling of 643156531264 in words is "six hundred forty-three billion, one hundred fifty-six million, five hundred thirty-one thousand, two hundred sixty-four".