640739216 has 80 divisors (see below), whose sum is σ = 1388661120. Its totient is φ = 284497920.

The previous prime is 640739201. The next prime is 640739227. The reversal of 640739216 is 612937046.

It is a self number, because there is not a number n which added to its sum of digits gives 640739216.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 634520 + ... + 635528.

It is an arithmetic number, because the mean of its divisors is an integer number (17358264).

Almost surely, 2^640739216 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 640739216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (694330560).

640739216 is an abundant number, since it is smaller than the sum of its proper divisors (747921904).

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

640739216 is a wasteful number, since it uses less digits than its factorization.

640739216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1144 (or 1138 counting only the distinct ones).

The product of its (nonzero) digits is 54432, while the sum is 38.

The square root of 640739216 is about 25312.8271040593. The cubic root of 640739216 is about 862.1055384764.

The spelling of 640739216 in words is "six hundred forty million, seven hundred thirty-nine thousand, two hundred sixteen".