641305728 has 256 divisors, whose sum is σ = 2211360000. Its totient is φ = 182891520.

The previous prime is 641305669. The next prime is 641305747. The reversal of 641305728 is 827503146.

641305728 is a `hidden beast` number, since 641 + 3 + 0 + 5 + 7 + 2 + 8 = 666.

It is a super-2 number, since 2×641305728² = 822546073531219968, 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 = 641305692 and 641305701.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1185138 + ... + 1185678.

It is an arithmetic number, because the mean of its divisors is an integer number (8638125).

Almost surely, 2^641305728 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 641305728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1105680000).

641305728 is an abundant number, since it is smaller than the sum of its proper divisors (1570054272).

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

641305728 is an equidigital number, since it uses as much as digits as its factorization.

641305728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 585 (or 553 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

The square root of 641305728 is about 25324.0148475711. The cubic root of 641305728 is about 862.3595415888.

The spelling of 641305728 in words is "six hundred forty-one million, three hundred five thousand, seven hundred twenty-eight".