640213605440 has 112 divisors (see below), whose sum is σ = 1531463546160. Its totient is φ = 254919475200.

The previous prime is 640213605403. The next prime is 640213605491. The reversal of 640213605440 is 44506312046.

It can be written as a sum of positive squares in 8 ways, for example, as 7972346944 + 632241258496 = 89288^2 + 795136^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 640213605440.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 81025490 + ... + 81033390.

Almost surely, 2^640213605440 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 640213605440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (765731773080).

640213605440 is an abundant number, since it is smaller than the sum of its proper divisors (891249940720).

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

640213605440 is a wasteful number, since it uses less digits than its factorization.

640213605440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9040 (or 9030 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 35.

Adding to 640213605440 its reverse (44506312046), we get a palindrome (684719917486).

The spelling of 640213605440 in words is "six hundred forty billion, two hundred thirteen million, six hundred five thousand, four hundred forty".