641564197 has 4 divisors (see below), whose sum is σ = 642020940. Its totient is φ = 641107456.

The previous prime is 641564179. The next prime is 641564291. The reversal of 641564197 is 791465146.

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 73170916 + 568393281 = 8554^2 + 23841^2 .

It is a cyclic number.

It is not a de Polignac number, because 641564197 - 2⁷ = 641564069 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641564107) 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 3 ways as a sum of consecutive naturals, for example, 226258 + ... + 229075.

It is an arithmetic number, because the mean of its divisors is an integer number (160505235).

Almost surely, 2^641564197 is an apocalyptic number.

It is an amenable number.

641564197 is a deficient number, since it is larger than the sum of its proper divisors (456743).

641564197 is a wasteful number, since it uses less digits than its factorization.

641564197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 456742.

The product of its digits is 181440, while the sum is 43.

The square root of 641564197 is about 25329.1175724698. The cubic root of 641564197 is about 862.4753798755.

The spelling of 641564197 in words is "six hundred forty-one million, five hundred sixty-four thousand, one hundred ninety-seven".