641091728 has 20 divisors (see below), whose sum is σ = 1242865020. Its totient is φ = 320352384.

The previous prime is 641091727. The next prime is 641091733. The reversal of 641091728 is 827190146.

It can be written as a sum of positive squares in 2 ways, for example, as 612661504 + 28430224 = 24752^2 + 5332^2 .

It is a junction number, because it is equal to n+sod(n) for n = 641091691 and 641091700.

It is not an unprimeable number, because it can be changed into a prime (641091727) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 17426 + ... + 39822.

It is an arithmetic number, because the mean of its divisors is an integer number (62143251).

Almost surely, 2^641091728 is an apocalyptic number.

It is an amenable number.

641091728 is a deficient number, since it is larger than the sum of its proper divisors (601773292).

641091728 is a wasteful number, since it uses less digits than its factorization.

641091728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24194 (or 24188 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 38.

The square root of 641091728 is about 25319.7892566269. The cubic root of 641091728 is about 862.2636094591.

The spelling of 641091728 in words is "six hundred forty-one million, ninety-one thousand, seven hundred twenty-eight".