640656213563 has 24 divisors (see below), whose sum is σ = 696111277008. Its totient is φ = 589054289472.

The previous prime is 640656213553. The next prime is 640656213629. The reversal of 640656213563 is 365312656046.

It is not a de Polignac number, because 640656213563 - 2¹² = 640656209467 is a prime.

It is not an unprimeable number, because it can be changed into a prime (640656213553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1427381 + ... + 1821737.

It is an arithmetic number, because the mean of its divisors is an integer number (29004636542).

Almost surely, 2^640656213563 is an apocalyptic number.

640656213563 is a deficient number, since it is larger than the sum of its proper divisors (55455063445).

640656213563 is a wasteful number, since it uses less digits than its factorization.

640656213563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 394523 (or 394500 counting only the distinct ones).

The product of its (nonzero) digits is 2332800, while the sum is 47.

The spelling of 640656213563 in words is "six hundred forty billion, six hundred fifty-six million, two hundred thirteen thousand, five hundred sixty-three".