640434238840 has 64 divisors (see below), whose sum is σ = 1572556032000. Its totient is φ = 232799091840.

The previous prime is 640434238831. The next prime is 640434238867. The reversal of 640434238840 is 48832434046.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 928701 + ... + 1464019.

It is an arithmetic number, because the mean of its divisors is an integer number (24571188000).

Almost surely, 2^640434238840 is an apocalyptic number.

It is an amenable number.

640434238840 is an abundant number, since it is smaller than the sum of its proper divisors (932121793160).

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

640434238840 is a wasteful number, since it uses less digits than its factorization.

640434238840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 538060 (or 538056 counting only the distinct ones).

The product of its (nonzero) digits is 1769472, while the sum is 46.

The spelling of 640434238840 in words is "six hundred forty billion, four hundred thirty-four million, two hundred thirty-eight thousand, eight hundred forty".