640065323857 has 2 divisors, whose sum is σ = 640065323858. Its totient is φ = 640065323856.

The previous prime is 640065323809. The next prime is 640065323869. The reversal of 640065323857 is 758323560046.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 638962021201 + 1103302656 = 799351^2 + 33216^2 .

It is a cyclic number.

It is not a de Polignac number, because 640065323857 - 2²³ = 640056935249 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 640065323857.

It is not a weakly prime, because it can be changed into another prime (640065323257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320032661928 + 320032661929.

It is an arithmetic number, because the mean of its divisors is an integer number (320032661929).

Almost surely, 2^640065323857 is an apocalyptic number.

It is an amenable number.

640065323857 is a deficient number, since it is larger than the sum of its proper divisors (1).

640065323857 is an equidigital number, since it uses as much as digits as its factorization.

640065323857 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3628800, while the sum is 49.

The spelling of 640065323857 in words is "six hundred forty billion, sixty-five million, three hundred twenty-three thousand, eight hundred fifty-seven".