641783808 has 72 divisors (see below), whose sum is σ = 1853642700. Its totient is φ = 213921792.

The previous prime is 641783777. The next prime is 641783851. The reversal of 641783808 is 808387146.

It is a tau number, because it is divible by the number of its divisors (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1023 + ... + 35841.

Almost surely, 2^641783808 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 641783808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (926821350).

641783808 is an abundant number, since it is smaller than the sum of its proper divisors (1211858892).

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

641783808 is a wasteful number, since it uses less digits than its factorization.

641783808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34847 (or 34824 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 45.

The square root of 641783808 is about 25333.4523505976. The cubic root of 641783808 is about 862.5737786919.

The spelling of 641783808 in words is "six hundred forty-one million, seven hundred eighty-three thousand, eight hundred eight".