641787917 has 2 divisors, whose sum is σ = 641787918. Its totient is φ = 641787916.

The previous prime is 641787911. The next prime is 641787959. The reversal of 641787917 is 719787146.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 379704196 + 262083721 = 19486^2 + 16189^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-641787917 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (641787911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320893958 + 320893959.

It is an arithmetic number, because the mean of its divisors is an integer number (320893959).

Almost surely, 2^641787917 is an apocalyptic number.

It is an amenable number.

641787917 is a deficient number, since it is larger than the sum of its proper divisors (1).

641787917 is an equidigital number, since it uses as much as digits as its factorization.

641787917 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 592704, while the sum is 50.

The square root of 641787917 is about 25333.5334487710. The cubic root of 641787917 is about 862.5756195548.

The spelling of 641787917 in words is "six hundred forty-one million, seven hundred eighty-seven thousand, nine hundred seventeen".