640565320556 has 18 divisors (see below), whose sum is σ = 1304007974388. Its totient is φ = 274527994440.

The previous prime is 640565320513. The next prime is 640565320561. The reversal of 640565320556 is 655023565046.

It is a super-2 number, since 2×640565320556² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 640565320556.

It is an unprimeable number.

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 in 5 ways as a sum of consecutive naturals, for example, 1634095010 + ... + 1634095401.

It is an arithmetic number, because the mean of its divisors is an integer number (72444887466).

Almost surely, 2^640565320556 is an apocalyptic number.

It is an amenable number.

640565320556 is an abundant number, since it is smaller than the sum of its proper divisors (663442653832).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

640565320556 is a wasteful number, since it uses less digits than its factorization.

640565320556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3268190429 (or 3268190420 counting only the distinct ones).

The product of its (nonzero) digits is 3240000, while the sum is 47.

The spelling of 640565320556 in words is "six hundred forty billion, five hundred sixty-five million, three hundred twenty thousand, five hundred fifty-six".