641661321 has 24 divisors (see below), whose sum is σ = 996188544. Its totient is φ = 366310560.

The previous prime is 641661299. The next prime is 641661329. The reversal of 641661321 is 123166146.

It is not a de Polignac number, because 641661321 - 2¹⁰ = 641660297 is a prime.

It is not an unprimeable number, because it can be changed into a prime (641661329) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 273871 + ... + 276203.

It is an arithmetic number, because the mean of its divisors is an integer number (41507856).

Almost surely, 2^641661321 is an apocalyptic number.

It is an amenable number.

641661321 is a deficient number, since it is larger than the sum of its proper divisors (354527223).

641661321 is a wasteful number, since it uses less digits than its factorization.

641661321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4221 (or 4214 counting only the distinct ones).

The product of its digits is 5184, while the sum is 30.

The square root of 641661321 is about 25331.0347400180. The cubic root of 641661321 is about 862.5188999849.

The spelling of 641661321 in words is "six hundred forty-one million, six hundred sixty-one thousand, three hundred twenty-one".