641565021 has 8 divisors (see below), whose sum is σ = 855670144. Its totient is φ = 427584960.

The previous prime is 641565019. The next prime is 641565049. The reversal of 641565021 is 120565146.

641565021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 641565021 - 2¹ = 641565019 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 641565021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641565721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18556 + ... + 40341.

It is an arithmetic number, because the mean of its divisors is an integer number (106958768).

Almost surely, 2^641565021 is an apocalyptic number.

It is an amenable number.

641565021 is a deficient number, since it is larger than the sum of its proper divisors (214105123).

641565021 is a wasteful number, since it uses less digits than its factorization.

641565021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62531.

The product of its (nonzero) digits is 7200, while the sum is 30.

The square root of 641565021 is about 25329.1338383293. The cubic root of 641565021 is about 862.4757491186.

The spelling of 641565021 in words is "six hundred forty-one million, five hundred sixty-five thousand, twenty-one".