641571840 has 880 divisors, whose sum is σ = 2996021952. Its totient is φ = 127401984.

The previous prime is 641571809. The next prime is 641571863. The reversal of 641571840 is 48175146.

It is a happy number.

641571840 is a `hidden beast` number, since 6 + 4 + 1 + 571 + 84 + 0 = 666.

It is a super-2 number, since 2×641571840² = 823228851761971200, which contains 22 as substring.

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

It is a junction number, because it is equal to n+sod(n) for n = 641571795 and 641571804.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 37739512 + ... + 37739528.

Almost surely, 2^641571840 is an apocalyptic number.

641571840 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 641571840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1498010976).

641571840 is an abundant number, since it is smaller than the sum of its proper divisors (2354450112).

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

641571840 is a wasteful number, since it uses less digits than its factorization.

641571840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74 (or 47 counting only the distinct ones).

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

The square root of 641571840 is about 25329.2684458119. The cubic root of 641571840 is about 862.4788047722.

It can be divided in two parts, 641571 and 840, that added together give a triangular number (642411 = T₁₁₃₃).

The spelling of 641571840 in words is "six hundred forty-one million, five hundred seventy-one thousand, eight hundred forty".