640908857559 has 8 divisors (see below), whose sum is σ = 856776333312. Its totient is φ = 426156976760.

The previous prime is 640908857551. The next prime is 640908857581. The reversal of 640908857559 is 955758809046.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 640908857559 - 2³ = 640908857551 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 640908857559.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640908857551) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 278897397 + ... + 278899694.

It is an arithmetic number, because the mean of its divisors is an integer number (107097041664).

Almost surely, 2^640908857559 is an apocalyptic number.

640908857559 is a deficient number, since it is larger than the sum of its proper divisors (215867475753).

640908857559 is a wasteful number, since it uses less digits than its factorization.

640908857559 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 557797477.

The product of its (nonzero) digits is 108864000, while the sum is 66.

The spelling of 640908857559 in words is "six hundred forty billion, nine hundred eight million, eight hundred fifty-seven thousand, five hundred fifty-nine".