640871735916767 has 2 divisors, whose sum is σ = 640871735916768. Its totient is φ = 640871735916766.

The previous prime is 640871735916619. The next prime is 640871735916809. The reversal of 640871735916767 is 767619537178046.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 640871735916767 - 2¹⁰ = 640871735915743 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640871735916067) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320435867958383 + 320435867958384.

It is an arithmetic number, because the mean of its divisors is an integer number (320435867958384).

Almost surely, 2^{640871735916767} is an apocalyptic number.

640871735916767 is a deficient number, since it is larger than the sum of its proper divisors (1).

640871735916767 is an equidigital number, since it uses as much as digits as its factorization.

640871735916767 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2240421120, while the sum is 77.

The spelling of 640871735916767 in words is "six hundred forty trillion, eight hundred seventy-one billion, seven hundred thirty-five million, nine hundred sixteen thousand, seven hundred sixty-seven".