641700864 has 330 divisors, whose sum is σ = 2236122330. Its totient is φ = 177020928.

The previous prime is 641700847. The next prime is 641700877. The reversal of 641700864 is 468007146.

641700864 is a `hidden beast` number, since 641 + 7 + 0 + 0 + 8 + 6 + 4 = 666.

It can be written as a sum of positive squares in only one way, i.e., 553190400 + 88510464 = 23520^2 + 9408^2 .

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 22127602 + ... + 22127630.

Almost surely, 2^641700864 is an apocalyptic number.

641700864 is a gapful number since it is divisible by the number (64) 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 641700864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1118061165).

641700864 is an abundant number, since it is smaller than the sum of its proper divisors (1594421466).

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

641700864 is an equidigital number, since it uses as much as digits as its factorization.

641700864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83 (or 41 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 36.

The square root of 641700864 is about 25331.8152527607. The cubic root of 641700864 is about 862.5366174750.

The spelling of 641700864 in words is "six hundred forty-one million, seven hundred thousand, eight hundred sixty-four".