640644550524 has 72 divisors (see below), whose sum is σ = 1766830993200. Its totient is φ = 194112172800.

The previous prime is 640644550519. The next prime is 640644550529. The reversal of 640644550524 is 425055446046.

640644550524 is a `hidden beast` number, since 6 + 4 + 0 + 6 + 44 + 550 + 52 + 4 = 666.

It is an interprime number because it is at equal distance from previous prime (640644550519) and next prime (640644550529).

It is a self number, because there is not a number n which added to its sum of digits gives 640644550524.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640644550529) 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 in 23 ways as a sum of consecutive naturals, for example, 3494014 + ... + 3672794.

It is an arithmetic number, because the mean of its divisors is an integer number (24539319350).

Almost surely, 2^640644550524 is an apocalyptic number.

It is an amenable number.

640644550524 is an abundant number, since it is smaller than the sum of its proper divisors (1126186442676).

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

640644550524 is a wasteful number, since it uses less digits than its factorization.

640644550524 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 187851 (or 187846 counting only the distinct ones).

The product of its (nonzero) digits is 2304000, while the sum is 45.

The spelling of 640644550524 in words is "six hundred forty billion, six hundred forty-four million, five hundred fifty thousand, five hundred twenty-four".