640889828866 has 32 divisors (see below), whose sum is σ = 1185244824960. Its totient is φ = 253632627456.

The previous prime is 640889828863. The next prime is 640889828867. The reversal of 640889828866 is 668828988046.

It is not an unprimeable number, because it can be changed into a prime (640889828861) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25391296 + ... + 25416523.

It is an arithmetic number, because the mean of its divisors is an integer number (37038900780).

Almost surely, 2^640889828866 is an apocalyptic number.

640889828866 is a deficient number, since it is larger than the sum of its proper divisors (544354996094).

640889828866 is a wasteful number, since it uses less digits than its factorization.

640889828866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50807898.

The product of its (nonzero) digits is 509607936, while the sum is 73.

It can be divided in two parts, 640889 and 828866, that added together give a triangular number (1469755 = T₁₇₁₄).

The spelling of 640889828866 in words is "six hundred forty billion, eight hundred eighty-nine million, eight hundred twenty-eight thousand, eight hundred sixty-six".