641085840 has 400 divisors, whose sum is σ = 2419845120. Its totient is φ = 156764160.

The previous prime is 641085817. The next prime is 641085853. The reversal of 641085840 is 48580146.

641085840 is a `hidden beast` number, since 64 + 10 + 8 + 584 + 0 = 666.

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 = 641085795 and 641085804.

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, 5047857 + ... + 5047983.

Almost surely, 2^641085840 is an apocalyptic number.

641085840 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 641085840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1209922560).

641085840 is an abundant number, since it is smaller than the sum of its proper divisors (1778759280).

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

641085840 is a wasteful number, since it uses less digits than its factorization.

641085840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212 (or 197 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 36.

The square root of 641085840 is about 25319.6729836702. The cubic root of 641085840 is about 862.2609696789.

The spelling of 641085840 in words is "six hundred forty-one million, eighty-five thousand, eight hundred forty".