641944817 has 2 divisors, whose sum is σ = 641944818. Its totient is φ = 641944816.

The previous prime is 641944759. The next prime is 641944829. The reversal of 641944817 is 718449146.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 629207056 + 12737761 = 25084^2 + 3569^2 .

It is a cyclic number.

It is not a de Polignac number, because 641944817 - 2¹⁶ = 641879281 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (641944217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320972408 + 320972409.

It is an arithmetic number, because the mean of its divisors is an integer number (320972409).

Almost surely, 2^641944817 is an apocalyptic number.

It is an amenable number.

641944817 is a deficient number, since it is larger than the sum of its proper divisors (1).

641944817 is an equidigital number, since it uses as much as digits as its factorization.

641944817 is an evil number, because the sum of its binary digits is even.

The product of its digits is 193536, while the sum is 44.

The square root of 641944817 is about 25336.6299455946. The cubic root of 641944817 is about 862.6459060590.

The spelling of 641944817 in words is "six hundred forty-one million, nine hundred forty-four thousand, eight hundred seventeen".