641571408 has 160 divisors (see below), whose sum is σ = 1931126400. Its totient is φ = 203664384.

The previous prime is 641571401. The next prime is 641571409. The reversal of 641571408 is 804175146.

It is a happy number.

641571408 is a `hidden beast` number, since 6 + 41 + 571 + 40 + 8 = 666.

It is a super-2 number, since 2×641571408² = 823227743126204928, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641571401) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1039516 + ... + 1040132.

It is an arithmetic number, because the mean of its divisors is an integer number (12069540).

Almost surely, 2^641571408 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 641571408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (965563200).

641571408 is an abundant number, since it is smaller than the sum of its proper divisors (1289554992).

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

641571408 is a wasteful number, since it uses less digits than its factorization.

641571408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 746 (or 734 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 36.

The square root of 641571408 is about 25329.2599181263. The cubic root of 641571408 is about 862.4786111898.

The spelling of 641571408 in words is "six hundred forty-one million, five hundred seventy-one thousand, four hundred eight".