640806535536 has 40 divisors (see below), whose sum is σ = 1695792910224. Its totient is φ = 208392368640.

The previous prime is 640806535531. The next prime is 640806535543. The reversal of 640806535536 is 635535608046.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640806535531) 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 7 ways as a sum of consecutive naturals, for example, 162804571 + ... + 162808506.

Almost surely, 2^640806535536 is an apocalyptic number.

It is an amenable number.

640806535536 is an abundant number, since it is smaller than the sum of its proper divisors (1054986374688).

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

640806535536 is a wasteful number, since it uses less digits than its factorization.

640806535536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 325613129 (or 325613123 counting only the distinct ones).

The product of its (nonzero) digits is 7776000, while the sum is 51.

The spelling of 640806535536 in words is "six hundred forty billion, eight hundred six million, five hundred thirty-five thousand, five hundred thirty-six".