641706560 has 84 divisors (see below), whose sum is σ = 1679708604. Its totient is φ = 233333760.

The previous prime is 641706521. The next prime is 641706607. The reversal of 641706560 is 65607146.

It can be written as a sum of positive squares in 2 ways, for example, as 335036416 + 306670144 = 18304^2 + 17512^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 641706560.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 30434 + ... + 47006.

It is an arithmetic number, because the mean of its divisors is an integer number (19996531).

Almost surely, 2^641706560 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 641706560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (839854302).

641706560 is an abundant number, since it is smaller than the sum of its proper divisors (1038002044).

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

641706560 is a wasteful number, since it uses less digits than its factorization.

641706560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16612 (or 16591 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 35.

The square root of 641706560 is about 25331.9276803010. The cubic root of 641706560 is about 862.5391695437.

The spelling of 641706560 in words is "six hundred forty-one million, seven hundred six thousand, five hundred sixty".