641128640 has 56 divisors (see below), whose sum is σ = 1529090160. Its totient is φ = 256048128.

The previous prime is 641128619. The next prime is 641128643. The reversal of 641128640 is 46821146.

It is a super-2 number, since 2×641128640² = 822091866056499200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a junction number, because it is equal to n+sod(n) for n = 641128597 and 641128606.

It is not an unprimeable number, because it can be changed into a prime (641128643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 281426 + ... + 283694.

Almost surely, 2^641128640 is an apocalyptic number.

It is an amenable number.

641128640 is an abundant number, since it is smaller than the sum of its proper divisors (887961520).

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

641128640 is a wasteful number, since it uses less digits than its factorization.

641128640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3169 (or 3159 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 32.

The square root of 641128640 is about 25320.5181621546. The cubic root of 641128640 is about 862.2801579300.

Adding to 641128640 its reverse (46821146), we get a palindrome (687949786).

The spelling of 641128640 in words is "six hundred forty-one million, one hundred twenty-eight thousand, six hundred forty".