640234784 has 72 divisors (see below), whose sum is σ = 1473631488. Its totient is φ = 273006720.

The previous prime is 640234759. The next prime is 640234787. The reversal of 640234784 is 487432046.

It is not an unprimeable number, because it can be changed into a prime (640234787) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 348749 + ... + 350579.

It is an arithmetic number, because the mean of its divisors is an integer number (20467104).

Almost surely, 2^640234784 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640234784, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (736815744).

640234784 is an abundant number, since it is smaller than the sum of its proper divisors (833396704).

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

640234784 is a wasteful number, since it uses less digits than its factorization.

640234784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2078 (or 2063 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 38.

The square root of 640234784 is about 25302.8611820877. The cubic root of 640234784 is about 861.8792437112.

The spelling of 640234784 in words is "six hundred forty million, two hundred thirty-four thousand, seven hundred eighty-four".