640644512305 has 16 divisors (see below), whose sum is σ = 879205443840. Its totient is φ = 438995466432.

The previous prime is 640644512213. The next prime is 640644512311. The reversal of 640644512305 is 503215446046.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640644512305 is a prime.

It is a super-2 number, since 2×640644512305² (a number of 24 digits) contains 22 as substring.

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 15 ways as a sum of consecutive naturals, for example, 6274210 + ... + 6375499.

It is an arithmetic number, because the mean of its divisors is an integer number (54950340240).

Almost surely, 2^640644512305 is an apocalyptic number.

It is an amenable number.

640644512305 is a deficient number, since it is larger than the sum of its proper divisors (238560931535).

640644512305 is a wasteful number, since it uses less digits than its factorization.

640644512305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12651168.

The product of its (nonzero) digits is 345600, while the sum is 40.

The spelling of 640644512305 in words is "six hundred forty billion, six hundred forty-four million, five hundred twelve thousand, three hundred five".