641661056 has 64 divisors (see below), whose sum is σ = 1364441760. Its totient is φ = 299520000.

The previous prime is 641661037. The next prime is 641661071. The reversal of 641661056 is 650166146.

It is a tau number, because it is divible by the number of its divisors (64).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 283931 + ... + 286181.

Almost surely, 2^641661056 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 641661056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (682220880).

641661056 is an abundant number, since it is smaller than the sum of its proper divisors (722780704).

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

641661056 is a wasteful number, since it uses less digits than its factorization.

641661056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2413 (or 2401 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 35.

The square root of 641661056 is about 25331.0295092797. The cubic root of 641661056 is about 862.5187812475.

The spelling of 641661056 in words is "six hundred forty-one million, six hundred sixty-one thousand, fifty-six".