641444728 has 32 divisors (see below), whose sum is σ = 1237219200. Its totient is φ = 311548032.

The previous prime is 641444719. The next prime is 641444747. The reversal of 641444728 is 827444146.

It is a super-2 number, since 2×641444728² = 822902678157987968, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 234553 + ... + 237271.

It is an arithmetic number, because the mean of its divisors is an integer number (38663100).

Almost surely, 2^641444728 is an apocalyptic number.

It is an amenable number.

641444728 is a deficient number, since it is larger than the sum of its proper divisors (595774472).

641444728 is a wasteful number, since it uses less digits than its factorization.

641444728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3559 (or 3555 counting only the distinct ones).

The product of its digits is 172032, while the sum is 40.

The square root of 641444728 is about 25326.7591294267. The cubic root of 641444728 is about 862.4218412127.

The spelling of 641444728 in words is "six hundred forty-one million, four hundred forty-four thousand, seven hundred twenty-eight".