641828881 has 4 divisors (see below), whose sum is σ = 642032100. Its totient is φ = 641625664.

The previous prime is 641828861. The next prime is 641828909. The reversal of 641828881 is 188828146.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 178890625 + 462938256 = 13375^2 + 21516^2 .

It is a cyclic number.

It is not a de Polignac number, because 641828881 - 2⁷ = 641828753 is a prime.

It is a super-2 number, since 2×641828881² = 823888624971424322, which contains 22 as substring.

It is a Duffinian number.

641828881 is a modest number, since divided by 28881 gives 6418 as remainder.

It is not an unprimeable number, because it can be changed into a prime (641828861) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 96796 + ... + 103213.

It is an arithmetic number, because the mean of its divisors is an integer number (160508025).

Almost surely, 2^641828881 is an apocalyptic number.

It is an amenable number.

641828881 is a deficient number, since it is larger than the sum of its proper divisors (203219).

641828881 is a wasteful number, since it uses less digits than its factorization.

641828881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 203218.

The product of its digits is 196608, while the sum is 46.

The square root of 641828881 is about 25334.3419294838. The cubic root of 641828881 is about 862.5939713057.

The spelling of 641828881 in words is "six hundred forty-one million, eight hundred twenty-eight thousand, eight hundred eighty-one".