641891568 has 60 divisors (see below), whose sum is σ = 1717479608. Its totient is φ = 206572800.

The previous prime is 641891563. The next prime is 641891629. The reversal of 641891568 is 865198146.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641891563) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 32418 + ... + 48318.

Almost surely, 2^641891568 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 641891568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (858739804).

641891568 is an abundant number, since it is smaller than the sum of its proper divisors (1075588040).

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

641891568 is a wasteful number, since it uses less digits than its factorization.

641891568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15970 (or 15935 counting only the distinct ones).

The product of its digits is 414720, while the sum is 48.

The square root of 641891568 is about 25335.5790934409. The cubic root of 641891568 is about 862.6220533847.

The spelling of 641891568 in words is "six hundred forty-one million, eight hundred ninety-one thousand, five hundred sixty-eight".