641020817 has 2 divisors, whose sum is σ = 641020818. Its totient is φ = 641020816.

The previous prime is 641020801. The next prime is 641020829. The reversal of 641020817 is 718020146.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 561168721 + 79852096 = 23689^2 + 8936^2 .

It is a cyclic number.

It is not a de Polignac number, because 641020817 - 2⁴ = 641020801 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 641020817.

It is not a weakly prime, because it can be changed into another prime (641020847) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320510408 + 320510409.

It is an arithmetic number, because the mean of its divisors is an integer number (320510409).

Almost surely, 2^641020817 is an apocalyptic number.

It is an amenable number.

641020817 is a deficient number, since it is larger than the sum of its proper divisors (1).

641020817 is an equidigital number, since it uses as much as digits as its factorization.

641020817 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2688, while the sum is 29.

The square root of 641020817 is about 25318.3889100393. The cubic root of 641020817 is about 862.2318166975.

The spelling of 641020817 in words is "six hundred forty-one million, twenty thousand, eight hundred seventeen".